To understand the unusual behavior of an adult client, a clinical psychologist carefully investigates the client's current life situation and his physical, social-cultural, and educational history. Which research method has the psychologist used?

(A) Case study

(B) Survey

(C) Correlation research

(D) Random sampling

The correct option is: (C) Correlation research

Explanation:

Correlational research refers to a type of research in which no experiment is conducted. In this method, the two variables are correlated and the statistical relationship between them is studied, without the influence of the extraneous variables. However, a correlational study or research is not capable of proving the cause-and-effect relationships.

The research method used by the psychologist is Correlation research.