Instructions: 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: Male dogs use pheromones in urine to mark their territory., Fact2: Generally, pheromones are volatile substances., Question: Male dogs use what in their urine to mark their territory? (A) hydrocarbons (B) volatile substances (C) kinetic energy (D) an area swollen with pus (E) Chemical energy (F) competing for resources (G) add a solute (H) Positive charges
Output:
B