=(C2=__Correct Answer__) assuming the answer is in C2.

This formula will produce the Excel logical values TRUE/FALSE. In the
formula above, if __Correct Answer__ is expected to be text, enclose in
double quotes. If it is supposed to be a number then no quotes.

If you want to sum the TRUE answers, you might want to use
=COUNTIF(E:E, TRUE)
assuming that all formulas that return true/false are in column E:E.

HTH
Kostis Vezerides