Detailed Instructions: 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.
See one example below:
Problem: Which part of a bicycle BEST moves in a circle?
(A) Seat (B) Frame (C) Foot pedal (D) Kickstand
Solution: C
Explanation: Seat, frame and Kickstand are static parts of the bicycle, even when bicycle moves. Foot pedal moves in a circle as bicycle moves.

Problem: Some antibiotics used to treat infections in humans are also used to treat chickens, but some groups oppose this practice. The overuse of the antibiotics will most likely influence the natural selection of which type of organisms?
(A) chickens that naturally make the antibiotics (B) microbes that are resistant to the antibiotics (C) microbes that are susceptible to the antibiotics (D) chickens that are resistant to infection
Solution:
B