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:
A pot is heated on a stove. Which process causes the metal handle of the pot to also become hot?
(A) combustion (B) convection (C) radiation (D) conduction

Ex Output:
D

Ex Input:
The body is made up of many systems that interact with one another. For example, the skeletal system and the muscular system work together to help the body move. Which system works with the respiratory system to distribute oxygen to the body?
(A) muscular system (B) digestive system (C) lymphatic system (D) circulatory system

Ex Output:
D

Ex Input:
Which factor is most likely to cause the number of rabbits living in an area to increase?
(A) less water (B) fewer predators (C) lack of shelter (D) limited food

Ex Output:
B