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: What would be the best way to determine the role of squirrels in a forest ecosystem?
(A) measure the length and mass of several squirrels (B) determine the genes that control squirrel traits (C) make field observations of squirrels in their natural habitat (D) read articles about the energy and nutrient requirements of squirrels
A:
C