Question

according to the rules of complementary base pairing in nucleic acids, cytosine would pair with the base

guanine.
adenine.
thymine.
cytosine.
uracil.

Explanation:

In nucleic - acids, cytosine (C) pairs with guanine (G) through three hydrogen bonds. Adenine (A) pairs with thymine (T) in DNA and with uracil (U) in RNA.

Answer:

A. guanine