Explanation
Correct answer: C.
Choice C is the best answer. The sentence presents the methods used in the study, noting that researchers tagged 138 female wood ducks with radio frequency ID trackers and recorded the number of nest boxes each duck visited.
Why the other choices are wrong
Choice A
Choice A is incorrect. While the sentence mentions an aspect of the study’s design (that the researchers recorded the number of nest boxes the wood ducks visited), it primarily focuses on a finding of the study rather than the methods the researchers used.
Choice B
Choice B is incorrect. While the sentence mentions an aspect of the study’s design (that the researchers tracked the number of nest boxes the wood ducks visited), it primarily focuses on a finding of the study rather than the methods the researchers used.
Choice D
Choice D is incorrect. The sentence misrepresents information from the notes. The researchers used radio frequency ID trackers to record the ducks’ visits; they didn’t investigate each site to look for evidence that it had been visited.