Answer: A sample study is mostly "TO LEARN HOW DIFFERENT PARAMETERS IN THE POPULATION BEHAVES TOGETHER". Option B is the most correct option.
Explanation: A sample study is a separated research samples that, that is used to study how selected parameters behaves. For example, selecting 10 student out of 100 student, to study how examination is related to student IQ. The 10 student are the sample study, while examination and IQ are the parameters to be studied how it behaves together.
Option B is the most correct option because it describes the basic function of a sample study to a research.