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: a generator converts kinetic energy into electrical energy, Fact2: Water behind a dam has potential energy that can be converted to kinetic energy., Question: a generator is used to turn water behind a what into electrical energy (A) dam (B) H20 (C) hot (D) sewer (E) pond (F) gutter (G) wind (H) Heat
A