Definition: 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: carbon dioxide concentrations in the air have increased over the last decade dramatically, Fact2: Carbon dioxide is formed by burning carbon., Question: Burning carbon concentrations have what? (A) Greenhouse gases (B) Chemical energy (C) reduced significantly (D) increased dramatically (E) Plant growth is reduced (F) heat energy (G) shrunk (H) declined spectacularly
Output:
D