Answer: .C. The population is the 10,900 respondents to the American Time Use Survey.
Explanation:
In statistics , Population is refer to a large group of individuals or observations that have same characteristics.
A sample is a subset drawn from it.
We are given that "The 2015 American Time Use survey contains data on how many minutes of sleep per night each of 10,900 survey participants estimated they get. An SRS (simple random sample) of 100 of the participants has a mean time of x¯=514.4 minutes. "
i.e. The population is 10,900 respondents to the American Time Use Survey.