Final answer:
The correct answer is C) Observational, as it is useful when participants cannot discuss their experiences. Longitudinal research tracks participants over time, participant observation is used by symbolic interactionists, and Freud's work with clients was a form of case study.
Step-by-step explanation:
Observational research is particularly useful when consumers are unable to talk about their experiences. The correct answer to the student's question is C) Observational.
Longitudinal research involves following a group of research participants for an extended period of time. Therefore, if we want to track changes over time in a specific cohort, longitudinal research is the appropriate method.
Symbolic interactionists would most likely use B) Participant observation as their research technique because it allows the researcher to observe and interact with the subjects in their natural environment, thereby gaining a deeper understanding of the social processes and meanings that the subjects give to their actions.
Freud's method of developing his theory of human personality through in-depth interviews over a long period of time with a few clients is known as a B) case study. The correct answer is C) Observational