I've run into one of those cases again where both the definite and indefinite article seem to work. And that makes me very confused as it makes it harder for me to grasp the concept of the articles. Here are some sample sentences that I found on the internet.
At the outset of the interview students were told that if they did not know an answer they could say "pass" and move on to the next question.
It is always a good idea to go over the test to make sure that you answered every question. If you do not know the answer, guess. You may get the right answer or partial credit.
It can be a reasoning exercise in which the student has to figure out an answer on her or his own.
The teacher-librarian serves as a guide to help students figure out the answer on their own.
Are the articles in these sentences interchangeable?
So if you are not talking about any specific answer (you don't know what an answer can be), do you use a or the, or it doesn't matter?
Again, the answer seems to be more common, according to my research, so is it more idiomatic?