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 natural aphrodisiacs., Question: What do male dogs use in urine to mark their territory? (A) Natural aphrodisiacs (B) competing for resources (C) Tails (D) Urine  cleaner (E) Something coming from a gland (F) Chemical energy (G) an area swollen with pus (H) Chew toys
[A]: A


[Q]: Fact1: Most people can survive only a few days without water., Fact2: Water is the best fluid for hydration., Question: What can people only survive a few days without? (A) dehydration (B) hydration (C) bacteria (D) sodium (E) food (F) yogurt (G) Chlorophyll (H) oxygen
[A]: B


[Q]: Fact1: All life relies on a relatively narrow range of pH, or acidity., Fact2: Acids have low pH's., Question: All life relies on a relatively narrow range of what? (A) voltage (B) Energy (C) sun's heat (D) low pHs (E) Decibels (F) spectrum (G) Light (H) sunlight
[A]:
D