Correct option is C
Diener and Crandall (1978) outlined key components of informed consent, which include:
-Voluntarism (A): Participation must be voluntary, without coercion.
-Information (C): Participants should be fully informed about the nature, purpose, and potential risks of the study.
-Comprehension (D): Participants must understand the information provided to them before giving consent.
"Researcher's competence" (B) is not a component of informed consent but rather a general ethical principle ensuring that researchers are qualified to conduct studies.