RNA is to U(Uracil) as DNA is to ?

Question

a. Cytosine (don't think so)
b. Guanine  (don't think so)
c. Thymine
d. Adenine

Steve · Answer

You can find your answer at the following site. http://en.wikipedia.org/wiki/Uracil_in_DNA

David · Answer

I read the article already, but I don't understand what is the answer. I am not sure if the question is referring to the the complementary base or something?