Detailed 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").
Q: Fact1: Male dogs use pheromones in urine to mark their territory., Fact2: Pheromones are a sub-category of semiochemicals., Question: What do dogs use to mark their territory? (A) water (B) Chemicals (C) layers of fat (D) food (E) Animal fur (F) heat energy (G) Scratches (H) heat produced
A:
B