It's a bullshit question. That's the problem with US media. They can't do substantive policy discussion because it's easier and more fun to do gotcha questions that can be added to their news timeline when somebody can't answer it as they want them to.
Asking a politician how they are going to pay for programs that will result in trillions of dollars of federal revenue to be spent is hardly a BS question. She should have a canned answer waiting for such a basic question that is a central component of the progressive platform, which btw is about a million miles from a gotcha question. The only problem I see is that the media aren't asking the same question when Republicans want to cut taxes and increase spending on defense etc. There needs to be an even application to the line of inquiry where both sides are taken to task about how they are going to fund their programs.