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: mechanical weathering is when rocks are broken down by mechanical means, Fact2: Water is a mechanical weathering force., Question: What  weathers rocks? (A) soil (B) streams (C) a delta (D) calcite (E) erosion (F) water (G) grass (H) the sun
Example Output: F

Example Input: 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
Example Output: D

Example Input: Fact1: a valley is formed by a river flowing, Fact2: And the fourth river is the Great River, the river Euphrates., Question: What does the Euphrates form? (A) erosion (B) a solute (C) a hurricane (D) Bodily water (E) a valley (F) Sediment (G) ancient ruins (H) a mountain
Example Output:
E