Definition: You are given a question on clinical knowledge. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: In a double stranded molecule of DNA, the ratio of purines : pyrimidines is:
(A)variable. (B)determined by the base sequence in RNA. (C)genetically determined. (D)always 1:1.

D