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.

[Q]: Some people carry a mutated allele of a particular gene that makes them resistant to HIV infection and AIDS. Which best describes this type of mutation?  
 (A) beneficial (B) asexual (C) harmful (D) unicellular
[A]: A


[Q]: The greatest amount of diversity can be found among which type of organism?  
 (A) plants (B) animals (C) bacteria (D) fungi
[A]: C


[Q]: The Water Quality Act of 1987 required the development of standards that would prevent toxic pollutants from reaching dangerous levels in bodies of water. This act affected the amounts of toxic chemicals that could be discharged into bodies of water. Which of the following would have been most regulated by this act?  
 (A) feed lots (B) private homes (C) paper mills (D) grocery stores
[A]:
C