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 Q]: A shallow container of salt water is placed in sunlight for a day. Which is the most likely result?  
 (A) All of the mixture will evaporate. (B) The salt will keep the water from evaporating. (C) The salt will separate from the water and float at the top of the container. (D) Only the water will evaporate and the salt will remain in the container.
[EX A]: D

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

[EX Q]: What is the MAJOR cause of acid rain?  
 (A) smelting ore (B) evaporation of polluted water (C) jet airplane exhaust high in the sky (D) sulfur combining with water vapor in the atmosphere
[EX A]:
D