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").
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Question: 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

Answer: C

Question: Fact1: volcanic ash in the atmosphere decreases the temperature by blocking the sun, Fact2: Ash clouds are a particular problem for aircraft., Question: What are particular problems for aircraft in the atmosphere? (A) transportation (B) clog airways (C) extremely low humidity (D) volcanic clouds (E) feedback mechanisms (F) negative feedback (G) gas spreads in the air (H) very complex

Answer: D

Question: Fact1: Yeast reproduce asexually by budding., Fact2: Yeast Saccharomyces cereviceae, or yeast, is a fungus., Question: What can reproduce asexually by budding? (A) Trees (B) bacteria (C) Flower buds (D) People (E) plants (F) Fungus (G) fungi (H) Flowers

Answer:
F