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: coal is used for generating heat by burning, Fact2: CO 2 and SO 2 are both given off when coal is burned to provide heat or to generate electricity., Question: When is coal burning _ is given off (A) CO 2 (B) energy (C) vaporization (D) SO2 (E) pollution (F) oxygen (G) carbon (H) smoke
Output:
A