We know that DNA is composed of nucleotides, each of which contains a nitrogen-containing base, a five-carbon sugar (deoxyribose), and a phosphate group. If the percentage of Guanine in one strand is 30%, what will be the percentage of cytosine in the complementary strand?

• A. 40%
• B. 20%
• C. 30%
• D. 25%

Answer: (C)