I once interviewed a candidate who (1) picked C to solve the programming problem they were given (some other languages were acceptable, and, actually, preferred

I once interviewed a candidate who (1) picked C to solve the programming problem they were given (some other languages were acceptable, and, actually, preferred) and (2) did not know how to dynamically allocate memory in that language. I did spot them the malloc() call (I certainly would not have wanted the interview to get bogged down for that), but yes, I did hold not knowing that against them in my evaluation.