Given the task definition and input, reply with output. You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

A scientist finds a metamorphic rock formation next to a magma chamber and determines that it was originally a sedimentary rock formation. He concludes that the temperature of the magma chamber caused the rock formation to become metamorphic. Which is another reliable explanation of how the rock formation was changed?
(A) weight of heavy machinery moving over the rocks (B) pressure on the rock formation inside Earth (C) a sandstorm that caused the rocks to be eroded (D) a quick burial of the rocks by tons of volcanic ash
B