Instructions: 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").
Input: Fact1: a windmill converts wind energy into electricity primarily by using mechanical energy, Fact2: Windmills tap into the energy of the wind using sails or vanes., Question: What do windmills use to convert energy? (A) Heat (B) fibers (C) copper (D) cycles (E) SO2 (F) Vanes (G) calcite (H) Lift
Output:
F