Many Promoters of a Hypothetical Conserved Gene Have Mostly Adenines

Multiple Choice

Many promoters of a hypothetical conserved gene have mostly adenines and thymines. What is the MOST likely reason for this high proportion of adenines and thymines?

A) RNA polymerases are better at incorporating uracils and thymines into RNA molecules than incorporating guanines and cytosines.
B) This is the region for separating template and nontemplate strands, and A-T base pairs are easier to separate than G-C base pairs.
C) Accessory proteins like sigma factors or transcription factors bind more easily to AT-rich sequences than they do to GC-rich sequences.
D) It is possible to create more unique sequences for recognition with adenines and thymines than it is with guanines and cytosines.
E) None of the other answer options is correct.