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.

The burning of fossil fuels affects the atmosphere by  
 (A) adding more heat and carbon dioxide. (B) reducing the amount of necessary heat. (C) taking water vapor out of the atmosphere. (D) putting more oxygen in the atmosphere.
A

A class made a solar cooker out of a large can. What color should they paint the can in order to collect the most heat?  
 (A) black (B) green (C) pink (D) white
A

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