Definition: 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: Scientists have created trains that use magnets to make the trains float above the tracks as they travel. These trains float because
(A) the track is waxed (B) the like poles repel (C) the train has a low density (D) a chemical change occurs
Output:
B