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.

[EX Q]: Dr. Tanaka discovered a new virus. The virus has a single strand of a nucleic acid, but she does not know if it is DNA or RNA. After running tests, she concludes that it is DNA. Which of the following would lead her to that conclusion?  
 (A) It contains uracil. (B) It contains adenine. (C) It contains thymine. (D) It contains cytosine.
[EX A]: C

[EX Q]: Surface mining is a type of mining that is done at the surface of Earth. In addition to supplying valuable minerals to industry, surface mining might also  
 (A) discourage landfills. (B) increase Earth's surface area. (C) eliminate groundwater pollution. (D) create recreational ponds and lakes.
[EX A]: D

[EX Q]: The best container for storing an unknown liquid is a  
 (A) plastic yogurt container. (B) clearly labeled glass jar. (C) paper orange juice container. (D) green plastic soda bottle.
[EX A]:
B