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.

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

Which of the following happens in our solar system?  
 (A) Earth revolves around the sun once per day. (B) The moon revolves around Earth once per day. (C) Earth revolves around the sun once per year. (D) The moon revolves around Earth once per year.
C

Scientists have monitored the amount of acid rainfall in Frederick County, Maryland, since 1982. Humans in Frederick County are affected by acid rain because acid rain alters  
 (A) wind patterns (B) air temperatures (C) the quality of water (D) the amount of precipitation

C