It should also be said that the question put to AOC was entirely improper. First, it's as much a military question as a policy question -- the American response would almost certainly vary depending on the circumstances of the hypothetical attack. Second, the American policy regarding Taiwan and China is so delicate, mostly interstitial and without any official formulation, that any statement coming from a member of Congress could have significant repercussions. I wonder if her pausing and stammering reflected that she was in real time processing how to deal with these factors.
What she should have said was, "I cannot make any statement about that. It's a question for the commander in chief after consultation with the Joint Chiefs of Staff. I don't want to say anything that might be construed as a commitment either way. All I can say is that I won't at this time give a definitive answer either way." Something like that. She'll learn.