Given the task definition and input, reply with output. 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: Viruses often infect bacteria., Fact2: Infected birds spread the bacteria in their droppings., Question: Viruses often can spread bacteria through what? (A) the skin (B) microscopes (C) contamination (D) covering (E) washing (F) alveoli (G) droppings (H) coating

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
G