You will be given a definition of a task first, then some input of the task.
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").

Fact1: boulders are formed by glaciers melting sometimes, Fact2: Glaciers are made of snow, ice and rock., Question: what melts sometimes to form boulders? (A) snow, ice, and rock (B) precipitation (C) thermal expansion (D) building blocks of organisms (E) rapid changes occur (F) 70-75 degrees Fahrenheit (G) permeable walls (H) holding nutrients
Output:
A