If they don’t want to hear the correct answer, let them modify the question to exclude postgres answers. Interviews are a 2 way street, you will miss out on great candidates by being this stupid.

On the one hand, interviewers can suck. They can be uninterested in understanding and embrace instead the role of a trigger-happy interrogator looking not for a good response - something that may very well require effort and considering new ideas on the part of the interviewer - but an excuse to cross you off the list. The interview begins to look like a game of "Guess what I'm thinking". Interviews should simulate a colleague asking you for help.

On the other hand, interviewees can give poor answers with no explanation. The interviewer should press for an explanation in those cases, of course, but perhaps some are trying to see if the interviewee instinctively provides at least some basic rationale behind the answer without having to be prodded each time, in which case it is a matter of communication habits and skills. Communication is essential, and it is under-emphasized and under-taught in so-called 'STEM' curricula.