WASHINGTON — Betsy DeVos, the education secretary, on Wednesday fiercely defended budget plans to spend $1.4 billion on the Trump administration’s expanded school choice agenda, but refused to say whether her office would withhold funds from private schools that discriminate against students.

In her first testimony to Congress since a bruising confirmation hearing in January, Ms. DeVos appeared unflappable as she told members of a House Appropriations subcommittee that the budget sought to empower states and parents to make decisions about students’ educations.

“We cannot allow any parent to feel their child is trapped in a school that isn’t meeting his or her unique needs,” Ms. DeVos told lawmakers.

But Democrats derided the education spending blueprint for the 2018 fiscal year as tone deaf to low-income and working-class Americans. Representative Rosa DeLauro of Connecticut, the top Democrat on the panel, called it “cruel” and “inhumane.”