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]: You wish to closely observe a small insect. Which tool is the best to use?  
 (A) a balance (B) a test tube (C) a telescope (D) a magnifying glass
[EX A]: D

[EX Q]: All of the following are functions of a cell membrane except  
 (A) surrounding and protecting the contents of the cell. (B) releasing waste products from the cell. (C) producing energy for cell processes. (D) allowing gases to enter the cell.
[EX A]: C

[EX Q]: When an ice cube melts, its state of matter changes from a  
 (A) gas to a liquid (B) solid to a liquid (C) liquid to a solid (D) solid to a gas
[EX A]:
B