Answer: A. What are the documented effects of noise pollution?
Explanation:
A research question refer to the question which the researcher centers his or her research on. The research question should be clear. The research question is regarded as the first step in any given research topic or project.
Since Kendra wants to understand the effects of noise pollution on people, the best question for Kendra to research in will be "What are the documented effects of noise pollution"?
This will provide a clear question on which the research will be based upon.