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:
Rocks that contain fragments of bones, shells, and plant remains are most likely
(A) crystals. (B) igneous. (C) sedimentary. (D) metamorphic.

Ex Output:
C

Ex Input:
In which state are molecules of a substance arranged in the most orderly way?
(A) gas (B) liquid (C) plasma (D) solid

Ex Output:
D

Ex Input:
New vaccines for diseases are being developed all the time. How do vaccines most likely help people?
(A) Vaccines help prevent illnesses. (B) Vaccines keep the environment cleaner. (C) Vaccines help cure people who are sick. (D) Vaccines kill bacteria that cause infections.

Ex Output:
A