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.

Which of these is the center of our solar system?  
 (A) Mars (B) The moon (C) Jupiter (D) The sun
D

Which is a process that occurs during photosynthesis?  
 (A) Plants take in oxygen and release sugar. (B) Plants take in sugar and release minerals. (C) Plants take in minerals and release carbon dioxide. (D) Plants take in carbon dioxide and release oxygen.
D

Which is an example of an organism that has been selectively bred for a particular genetic trait?  
 (A) cats that eat mice (B) cows that graze on grass (C) pigs that form large herds (D) chickens that lay large eggs

D