You will be given a definition of a task first, then some input of the task.
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: sonar is used to find the location of an object, Fact2: Sonar bounces sound waves off the bottom of the ocean., Question: Bouncing sound waves off the bottom of the ocean is used to find what? (A) locations of objects (B) body water (C) one celled organisms (D) hidden communities (E) atlantis (F) underwater cities (G) food and shelter (H) electromagnetic energy
Output:
A