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: Plants detect and respond to the daily cycle of light and darkness., Fact2: Plants are sensitive to light., Question: What are plants sensitive to? (A) Pollution (B) sun's heat (C) gravity (D) moon (E) competition (F) darkness (G) temperature (H) tides
F