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: friction causes the temperature of an object to increase, Fact2: Friction in bearings causes an increase of the temperature inside the bearing., Question: What increases the temperature of a bearing? (A) metal type (B) water (C) friction (D) Energy. (E) wind (F) speed (G) vaporization (H) energy
Output:
C