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.

When a cup of water at room temperature is put in a freezer, the water's state of matter will change from  
 (A) liquid to gas (B) gas to liquid (C) liquid to solid (D) solid to liquid
C

Which is a way the agricultural biotechnology industry could have a positive impact on the environment?  
 (A) by producing crops that are virus resistant (B) by making robots to replace large farm machines (C) by reducing the need for countries to import food (D) by increasing the use of wind farms that produce electricity
C

Sound waves are not able to travel through  
 (A) a cloud (B) a vacuum (C) metal (D) water

B