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:
Which two protein molecules are essential for muscle contraction and relaxation?
(A) actin and myosin (B) collagen and tubulin (C) hemoglobin and myoglobin (D) amylase and polymerase

Ex Output:
A

Ex Input:
Use of nuclear fuel would most likely reduce human contributions to which environmental problem?
(A) ozone thinning (B) landfill creation (C) shoreline erosion (D) greenhouse heating

Ex Output:
D

Ex Input:
What advantage do the offspring of a dandelion have by reproducing asexually?
(A) Reproduction occurs rapidly. (B) Reproductive competition is increased. (C) Mating compatibility improves. (D) Diversity increases between generations.

Ex Output:
A