Hey there!

Assuming that we are talking about an exam that has a few MCQ questions and you are supposed to be writing down on answer sheet as opposed to marking the options, as long as you mentioned the question number properly, like for instance, answer for question number 1 is _________, then you are safe.

However, if you have simply written down the answer without writing the option number including absence of the question number too, then you may be in trouble.

Hope this helps. Good luck!