Cozbi Mazariegos stays in shape these days by running room to room inside her Marin City apartment to answer questions from her kids, ages 7, 10 and 12. They’re all working at home on laptops issued by their school, Bayside Martin Luther King Jr. Academy.

Meanwhile, Shannon Bynum’s son, Kamari, 10, and daughter, Keyari, 8, who live nearby, are back on the Bayside MLK campus. Bynum had warned them, however, that if he heard they weren’t wearing masks, they’d have to learn remotely, too.

The two households, less than 3 miles apart, have found different answers to one of the most perplexing questions this fall: Should parents send their children back to school for classes during an ongoing pandemic or keep them at home?

At Bayside MLK, a K-8 school serving the ethnically and economically diverse community of Marin City, 103 children are attending class in person, including the Bynum children. The Mazariegos kids are among 12 learning remotely.

In March, the coronavirus consigned nearly all of the nation’s 55 million schoolchildren to home schooling. One by one, school districts across the country are weighing the risks of reopening. Some that have reopened have seen a spike in coronavirus cases among students who returned to class.

Bayside MLK was one of 15 Marin County schools that received waivers from the local public health department to reopen full time on Sept. 8, but officials gave parents the choice whether to send their children to campus or keep them home.

The start of classes was delayed for a week when one school employee contracted the virus, said Principal David Finnane. Once they started, the challenges mounted.

“This is the most mind-numbing time I’ve ever had as an educator,” said Finnane, who’s been a school principal for two decades.

“These are crazy days of temperature checks, telling third grade Jenny she entered the second grade gate at the wrong time, telling Xavier to use sanitizer on his elbow after he sneezes, reminding students not to touch this thing or that thing. It’s a job this school has never had to do and now we’re doing it every day, all day long.”

Health and safety protocols enacted by the school include staggered arrival times for students (via parent drop-offs), smaller classes, spaced-out desks, routine temperature and health checks, and an intensified cleaning schedule.

Mazariegos, 52, spent a difficult summer deciding whether to send Emily, 12, Ezekiel Jr., 10, and 7-year-old Evelyn back to class if and when school reopened in the fall.

But her husband, Ezekiel, a 42-year-old construction worker, had made up his mind. “He said, ‘Are you crazy? We can’t send our kids back to school without a vaccine,’” she recalled. “‘How do we know they’d be safe?’”

Mazariegos, who was a schoolteacher in her native Guatemala but now stays at home with her kids, has juggled the roles of teacher, tech consultant and even hall monitor in recent weeks.

School hadn’t been back in session for a week before her home Wi-Fi connection crashed. The two eldest kids could not connect to their Zoom instruction sessions, so Mazariegos called the school for help. To make sure they didn’t resort to computer games in the interim, she gave them textbooks to read.

“The phone was ringing, the kids were all calling my name from different rooms,” she said. “It was crazy.”

Single father Bynum, on the other hand, chose to send his two kids back to school.

“Kids learn from other kids, not just teachers,” said the 29-year-old real estate developer. “In school, they know what’s expected of them. It’s the best place for them to be.”

Finnane, the principal, had hoped all 115 students would return to classrooms. “Many kids doing distance learning just don’t have the same support network,” he said. “They might not have the resources, a quiet place to work, a supportive adult right there who can mentor and encourage them.”

And then there are the technical issues. Students who have stayed at home have experienced internet failures, Zoom glitches and computer bandwidth problems — “or when a teacher gives out the wrong Zoom link, all of which has already happened,” Finnane said.

A recent study by the Economic Policy Institute on the educational challenges posed by the pandemic found that remote-learning programs are effective only if students have consistent access to the internet and computers and if teachers receive targeted training and support for online instruction.

While researchers acknowledged the risk of virus infection is greater at school, they found that students who have not returned to the classroom are falling behind.

“Children’s academic performance is deteriorating during the pandemic, along with their progress on other developmental skills,” the study said.

When Bayside MLK resorted to remote teaching for the entire school in the spring, officials identified 41 students who were demonstrably falling behind, Finnane said. Standardized tests given to students this academic year will provide a report card on students’ success, he added.

Over the summer, Bayside MLK teachers received one day of training to perform online classes in addition to their at-school duties.

“A full day of online-learning training helps, but when it comes to the constant challenges of teaching, especially those with special needs, I’m not sure that’s sufficient,” said Emma García, who co-authored the Economic Policy Institute study.

Mazariegos knows this all too well. Her daughter Emily has comprehension issues that have kept her back a grade.

A quiet girl who loves animals and science, and who one day wants to become a veterinarian, the sixth grader relies on her mother to spend extra time reviewing lessons.

“She has to touch and feel things, to have a lesson demonstrated before she can best understand,” her mother said. “She can’t just sit in front of a computer reading some concept over and over and over.”

Mazariegos understands her daughter may fall another year behind but says she’ll take that chance. “If we lose her to COVID-19, that year is nothing,” she said. “This is a hard decision for any mother. But Emily is so afraid of the virus that sending her back to school would just be traumatizing.”

Bynum, whose fourth grade son, Kamari, suffers from attention deficit disorder, believes the classroom is the best place for the restless child. In March, when the school was closed at the start of the pandemic, Bynum got a taste of the demanding task of being a teacher.

“With two kids in two different grades asking me questions, I struggled to explain things,” he said. “It would have been easy for me to just tell them the answer, but the object of a good instructor is to teach them to find it themselves. And I had to learn that.”

Bynum has developed his own protocol. He requires his children to shower the moment they return from school, and they get regular lectures about hand-washing and common sense.

“If I even suspect they’re not wearing their masks, I’ll say, ‘OK, it’s back to the house and your laptop,’ and they’ll say, ‘Oh yeah, Dad, I’m wearing my mask.’”

Mazariegos remains comfortable with her decision, especially when she reads about all the COVID-19 outbreaks at schools and colleges.

Her kids aren’t so sure.

Second grader Evelyn, an outgoing girl, recently joined a Zoom lesson that included classmates she hadn’t seen in person for months.

“She cried,” her mother said. “She wanted to be back at school to see her friends.”