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.

Q: Scientists discovered that although infectious bacteria may develop immunity to antibiotic medications, some bacteria are unable to resist certain peptides, which act as natural antibiotic substances inside the human body. This discovery led to the development of which new technology?  
 (A) artificial substances that mimic human peptides (B) antibiotics that can be absorbed through the skin (C) bacteria that attack antibiotic-resistant organisms (D) antibiotics that adapt in response to bacterial immunity

A: A
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Q: Which mixture contains ingredients that can be easily separated?  
 (A) bread (B) fruit salad (C) ocean water (D) soda water

A: B
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Q: How could you scientifically determine the quietest place to study in your school?  
 (A) Ask your principal where the best place is to study. (B) Survey the student body to see where they like to study. (C) Record the level of decibels in various places in the school, and compare the results. (D) Have everyone be as quiet as possible, and then test the decibels in various places in your school.

A:
C
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