Answer:
B. direct, naturalistic, and unobtrusive
Explanation:
Direct observation: Direct observation is a famous technique that is used by a researcher. In this technique, the researcher sits passively and observe the subjects. What the subject is doing and what is behavior interpreted by a subject.
Naturalistic observation: This observation occurs in natural settings. In this technique the observe the behavior naturally. There is no biased occurrence in the behavior of a person.
Unobtrusive observation: This is the technique that is used by a researcher. In this technique, the subject is unaware that he is being observed by someone.