Instructions: In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").
Input: An example of pollution might be (A) recycling old glass to make a house (B) throwing plastic in the ocean (C) donating clothes to a thrift shop (D) Using old shirts to make a blanket
Output:
B