According to the principle of informed consent, the researcher does not have to inform potential participants about:
a. painful procedures involved in the study.
b. the potential of harm from the study.
c. the hypothesis of the study.
d. embarrassing questions they may be asked as part of the study.

The correct answer is C. The hypothesis of the study.

Explanation:

In research, informed consent implies the researcher needs to inform potential participants about different aspects of the research and their participation, in this way they can decide whether or not to participate. This includes explaining potential participants about possible harms or benefits, procedures they will be involved in, among others. However, the researcher is not forced to inform them about the hypothesis of the study as this might influence participants' answers or performance and thus make the research invalid.