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: increasing heat causes thermal expansion, Fact2: Thermal fatigue cracking is notably different than thermal expansion damage., Question: what can cause fatigue? (A) cigarettes (B) Dehydration (C) expansion (D) Pollution (E) influenza (F) hormones (G) sweating (H) smoking
C