Which of the following is a good test-taking strategy for short-answer questions?

a) if you don't know the exact answer, don't write anything.
b) if you don't know the exact answer, write down what you know. (this is the one i'm guessing is correct)
c) make your answer as short as possible
d) for all short-answer questions, list information that you know instead of writing complete sentences.

my explanation for the answer i think is correct( confirm this if you agree! ): i think b) is correct, because you do want to write something down, unlike a), which says to not write anything if you don't know the answer. i don't believe d) is correct either, but it is a strategy to you answer the question. you still wanna write full sentences to get credit. i also believe that c) isn't correct, because making your answers as short as possible won't you get full credit on your answer. if you write short, choppy sentences that make absolutely no sense, then you will end up with only some or none of the points for the question.