The population or the census is a set of all subjects that are targetted in the study. While the sample is a subset of the census or the population. The sample is the set of few subjects selected randomly from the population to make an inference about the population. Also, collecting information from the complete population is too time-consuming and too costly as well. Sometimes the size of the population is too large that it is practically not possible to collect data from everyone.

Therefore:

Option D) All of the above