Instructions: 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.
Input: The Mariana Trench is the deepest ocean trench on Earth. This trench occurs at a plate boundary where
(A) one plate is sliding past another. (B) one plate is being forced beneath another. (C) two plates are colliding into each other. (D) two plates are pulling apart from each other.
Output:
B