Q: 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.
Students want to compare the size of microorganism communities in 500-milliliter water samples from each of two ponds. Which factor most likely will affect the accuracy of their observations?
(A) the average temperature of the water samples (B) the brand of microscope slide used (C) the magnifying power of the microscope (D) the proper identification of each microorganism
A:
C