In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").

Fact1: Most genes contain the instructions for a single protein., Fact2: Genes are the basic unit of heredity., Question: What mostly contain the instructions for a single protein? (A) resistance activities (B) Veins and arteries. (C) A Greek letter (D) sensory neurons (E) fur seals (F) parasites (G) units of heredity (H) colors of the spectrum
G