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").

Ex Input:
Fact1: All life relies on a relatively narrow range of pH, or acidity., Fact2: Human life is dependent life., Question: what relies on a relatively narrow range of acidity? (A) gravity (B) mammals (C) animals (D) trees (E) humans (F) density (G) volume (H) potatoes

Ex Output:
E

Ex 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

Ex Output:
C

Ex Input:
Fact1: irradiating food can be used to kill existing microorganisms in the food, Fact2: Food irradiation is one tool for improving food safety by killing pathogenic microorganisms., Question: What does irradiating food do? (A) Relieve pain (B) enhance food's nutrients (C) improves food safety (D) allows growth of bacteria (E) increases food waste (F) chemical changes (G) get chemical reactions started (H) major threat to health

Ex Output:
C