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.

Water vapor sometimes condenses into stratus clouds that are in contact with the ground. What forms as a result of this process?  
 (A) ozone (B) methane (C) fog (D) smoke
C

Which of the following would be more likely to pollute a river?  
 (A) allowing beavers to build a dam (B) spreading fertilizer near the river (C) mowing the grass on the river bank (D) fishing from a bridge over the river
B

Which color baseball cap would absorb the most light on a sunny day?  
 (A) pink (B) black (C) white (D) yellow

B