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.

One of the main causes of acid rain is  
 (A) Waste from nuclear power plants (B) Spills from chemical manufacturing plants (C) Gases from burning fossil fuels (D) Gases from aerosol spray cans
C

There is a river at the base of Mount Tom. In the spring the water level is usually very high. In the summer it is lower. The higher level of water during the spring comes from  
 (A) hurricanes. (B) melting snow. (C) tornadoes. (D) evaporating water.
B

What property is the same for each atom of an element?  
 (A) energy (B) mass number (C) atomic number (D) number of neutrons

C