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 Q]: Fact1: a breathing mask is used for keeping harmful particles from entering the respiratory system, Fact2: Oxygen enters the respiratory system through the mouth and the nose., Question: Breathing masks are used to keep harmful particles from entering the mouth and the what? (A) body (B) eyes (C) air (D) skin (E) gullet (F) nose (G) ears (H) lungs
[EX A]: F

[EX Q]: Fact1: having food has a positive impact on an organism 's health, Fact2: Birds and animals eat such food ., Question: What generally has a positive impact on an organism's health? (A) stay warm (B) sex with multiple partners (C) smoking (D) exercise (E) nutrients (F) eating (G) Cooking (H) fasting
[EX A]: F

[EX Q]: Fact1: Ethologists usually study how animals behave in their natural environment., Fact2: Ethologists study animal behavior., Question: what study animals in their natural environment? (A) animal behaviorists (B) it keeps an organism warm (C) animal owners (D) biological diversity (E) animal hunters (F) retaining heat (G) by indirect light (H) animal eaters
[EX A]:
A