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.

Ex Input:
At what time on a sunny day will the shadow of the school's flagpole be the shortest?  
 (A) sunrise (B) noon (C) mid-afternoon (D) sunset

Ex Output:
B


Ex Input:
When would the highest tides occur along the Texas coast?  
 (A) at sunrise (B) at sunset (C) during a full moon (D) during a half moon

Ex Output:
C


Ex Input:
A science teacher is discussing the immune system with his class. Which statement should the teacher make about this system?  
 (A) It produces new cells to carry oxygen. (B) It produces chemicals to regulate growth. (C) It produces antibodies to fight bacteria. (D) It produces electrical signals to control the body.

Ex Output:

C