Which of the Following Is True About the Principles of Research

Which of the following is true about the principles of research design?

A) The design chosen for a given study depends on the answers provided by the population.
B) Research is almost always conducted on large populations and not on samples.
C) The way the different variables, used by researchers, influence each other is irrelevant to the research design.
D) The first step in obtaining a sample is for the researchers to decide the makeup of the entire group.