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.

Example Input: What is the main function of red blood cells?  
 (A) To fight disease in the body (B) To carry oxygen to all parts of the body (C) To remove carbon monoxide from all parts of the body (D) To produce materials which cause the blood to clot.
Example Output: B

Example Input: When the cardboard cone of a radio speaker vibrates, it produces a sound in the air around it. The cone produces this sound by transferring which of the following to the air around it?  
 (A) heat (B) current (C) wave motion (D) magnetic force
Example Output: C

Example Input: All stars start forming in the same manner. Some follow the life cycle of the Sun, while others turn into neutron stars or black holes. Which property determines the fate of a star as it develops?  
 (A) mass (B) location (C) luminosity (D) temperature
Example Output:
A