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 bright object with a long tail of glowing gases is in orbit around the Sun. This object is most likely
(A) a planet (B) a star (C) an asteroid (D) a comet

Ex Output:
D

Ex Input:
Four objects are on a wooden ramp. Which object is most likely to roll off the ramp if it is pushed gently?
(A) flat eraser (B) round ball (C) bent paper clip (D) wooden cube

Ex Output:
B

Ex Input:
Hydrogen gas and oxygen gas combine to form water. Which would be a more concise way of expressing what happens in this chemical reaction?
(A) write a chemical formula (B) write a chemical equation (C) describe the rearrangement of the atoms (D) describe the procedure for creating this change

Ex Output:
B