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: Like coal, petroleum is a fossil fuel., Question: What is used for generating heat by burning? (A) Calcium carbonate (B) carbon dioxide (C) fossil fuels (D) clouds (E) peachleaf willow (F) space (G) calcite (H) sunlight
C