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: Birds are endothermic tetrapod vertebrates., Fact2: Class Aves is for the birds, literally., Question: What kind of animal would be an endothermic tetrapod vertebrate? (A) animals in the class aves (B) barks and snarls (C) passenger pigeons (D) Something that is self-aware (E) Generating heat (F) retaining heat (G) absorb light energy (H) it keeps an organism warm
Output:
A