And it is answered very easily by asking, who is donating to them?
You don't want to do that work because doing so would reveal that most -if not all- of the donations those specific folks received were from small donors.
Opensecrets even lists out PAC spending and fundraising for candidates. On AOC's Opensecrets page of donors, that % is literally zero.
So AOC is "bought" by small donors that she engages not at $10,000-a-plate dinners in wine caves, but via her social media platforms. That's how a modern politician reaches their constituency to know what their constituency wants. She also does town halls all the time, is totally willing to sit down for interviews, and most importantly puts in the effort in her actual job duties; meeting with constituents, crafting and voting on legislation, attending committee hearings. Those three things are solely an elected Representative's job as defined by our Constitution.
Notice how "fundraising" isn't included there.