Answer:
naturalistic observation
Explanation:
Naturalistic observation: In psychological research, the term "naturalistic observation" is determined as a specific research method whereby different individuals or participants are being observed or noticed in their "natural setting". Generally, social scientists and psychologists utilize naturalistic observation to study particular cultural & social setting that couldn't be looking into or investigated by other means, like, hospitals, prisons, etc.
In the question above, Dr X should use naturalistic observation.
