Given the task definition and input, reply with output. 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: extreme heat and pressure change rock into metamorphic rock, Fact2: Marble is a metamorphic rock., Question: What can change rock into marble? (A) extreme heat and pressure (B) heat is produced (C) air pressure (D) It gets heated up (E) barometric pressure (F) slow heat transfer (G) heat production (H) exposure to cold
A