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").

Example Input: Fact1: gravity causes objects that have mass to be pulled down on a planet, Fact2: Rocks have mass., Question: What does gravity cause to be pulled down on a planet? (A) matter (B) heat (C) earth (D) solutes (E) oceans (F) Rocks (G) people (H) Lift
Example Output: F

Example Input: Fact1: Biomass is the total mass of organisms at a trophic level., Fact2: Each stage is a trophic level., Question: The total mass of organisms in an environmental stage is called what? (A) food pyramid (B) extinction (C) ecological pyramid (D) food chain (E) vegetation (F) food (G) ligt (H) biomass
Example Output: H

Example Input: Fact1: Antigens are molecules that the immune system recognizes as foreign to the body., Fact2: Children are born with an immature immune, or defense, system., Question: What are molecules that the defense system recognizes as foreign to the body? (A) Allergies (B) lungs (C) antigens (D) bacteria (E) parasites (F) atoms (G) red blood cells (H) acetic acid
Example Output:
C