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.

Input: Consider Input: Water at 20C in an uncovered pan is evaporating very slowly. What could be done to the water to make it evaporate more quickly?
(A) Cover it. (B) Heat it. (C) Place it in the dark. (D) Put salt in it.

Output: B

Input: Consider Input: One of the main causes of acid rain is
(A) Waste from nuclear power plants (B) Spills from chemical manufacturing plants (C) Gases from burning fossil fuels (D) Gases from aerosol spray cans

Output: C

Input: Consider Input: During its lifetime, a star will evolve through several stages. In which stage does a star spend most of its life?
(A) red giant (B) red dwarf (C) white dwarf (D) main sequence
Output: D