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.

[Q]: 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.
[A]: B


[Q]: Parents with freckles often have children with freckles. This occurs because  
 (A) freckles develop from light. (B) certain foods cause freckles. (C) certain habits cause freckles. (D) freckles are an inherited trait.
[A]: D


[Q]: The students in an engineering class built a robot that stacks wooden blocks. A built-in computer controls the movement of the robot. The computer in the robot performs a function most similar to which part of the human body?  
 (A) lungs (B) heart (C) brain (D) arms
[A]:
C