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").
Q: Fact1: faulting of rock in Earth 's crust causes earthquakes, Fact2: Earthquakes tremors both mild and moderate are frequent occurrences in the park and preserve., Question: What causes tremors? (A) thunder (B) Electrical energy (C) fire (D) faulting of rocks (E) sensory neurons (F) energy of moving objects (G) tornadoes (H) electromagnetic energy
A:
D