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: Sheri went on a field trip with her class and saw a stream with floating garbage. How could this pollution affect humans?
(A) There may not be enough drinking water. (B) There may not be enough water in the water cycle. (C) There may not be enough oxygen for humans to breathe.
Output:
A