You are given a science question (hard-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.

As a sample of mercury changes state from liquid to solid, the atoms of the sample
(A) move closer together and have less kinetic energy. (B) move closer together and have more kinetic energy. (C) move farther apart and have less kinetic energy. (D) move farther apart and have more kinetic energy.
A