If anyone deserves an A+ this week it's Marisela Castro, a daughter of farmworkers who turned her Social Action class project at San Jose State University into a campaign to increase the local minimum wage.

On Monday her activism paid off, as 70,000 workers in San Jose enjoyed the nation's single largest minimum-wage increase, a 25 percent raise from $8 to $10 an hour, amounting to a $4,000 annual bump in pay for a full time worker to $22,080.

"I never doubted for a minute we could make this happen," said Castro, 28, who grew up in agriculture-rich Gilroy, where her parents and at times Castro picked garlic, lettuce and other vegetables in nearby fields.

While putting herself through college in 2011, Castro worked at an after-school program with low-income children who slipped snacks into their backpacks because there wasn't enough food at home.

Meanwhile in her sociology classes she was reading about how a minimum wage job leaves workers — especially those in one of the wealthiest regions of the country — in severe poverty.

"When I understood what was happening in our community, it started to really piss me off," she said.

In her Social Action class, sociology professor Scott Myers-Lipton assigned everyone to create an advocacy campaign. Castro and several classmates chose raising the minimum wage.

"At some point during that semester it hit me that this was much more than a class project," said classmate Leila McCabe, 31, who graduated and now works for a nonprofit. "But we were determined and now that it's happening, it's amazing, very emotional."

The students started with a poll that found 70 percent of the community favored an increase. They later learned one in five local workers would be directly impacted. Then they asked Cindy Chavez, who heads the nonprofit Working Partnerships USA, for support.

"When you live in a place as expensive as Silicon Valley, the fact that people here are paid so little and still figure out a way to hang on by their fingernails here is just sort of astounding," Chavez said. "We were very excited to take this on."

In November, 59 percent of San Jose voters approved the raise, making it the largest city in the U.S. to date to raise its minimum wage.

"In providing the largest jump in the minimum wage in America, Silicon Valley once again shows that it is a national leader," said U.S. Rep. Michael Honda, who represents the region.

Voters in Long Beach and Albuquerque, N.M., also approved similar measures in November. San Francisco's $10.55 an hour minimum wage, the highest in the country, took effect on Jan. 1.

Nineteen states, including California, have also raised their minimum wage, and Congress is now considering a law that would raise the federal minimum wage from $7.25 to $10.10 an hour.

Stanford Center on Poverty and Inequality associate director Charles Varner said raising minimum wage can help address growing disparity.

"The rising inequality in the last four decades is a problem of the restructuring of our economy," he said.

Opponents in San Jose said raising the minimum wage would cripple San Jose's fragile economic recovery, causing employees to lose hours or even their jobs. On Monday, opponent Scott Knies, executive director of San Jose's Downtown Association, said some businesses have already raised prices or cut hours.

But Knies was trying make the best of it, launching "Earn 'n Spend in San Jose," a campaign that urges workers who benefit from the raise to keep their dollars local.

Nick Taptelis, owner of Philz Coffee, raised his wages to $10 an hour more than a month ago and has seen happier workers which in turn brings more customers into his bustling shop near the university campus.

Castro, 28, was beaming as her former professor patted her on the back.

"This shows that regular folks can change economic policy in this country," said Myers-Lipton.

Castro said her professor was "very inspiring."

So what grade did she end up with?

"Actually I got a B," she said. "He's also a really hard grader."