Informed consent means that:_______.
a) subjects agree to allow the experimenter to use their data for approved purposes.
b) subjects agree to participate in a study after receiving complete information about the nature and purpose of the study.
c) subjects agree to participate in a study after receiving complete information about the nature, purpose, and hypothesis of the study.
d) the institutional review board has agreed to allow the researcher to recruit subjects for an approved experiment.

In research, the term informed consent refers to the process in which researchers get a voluntary agreement from participants of the study where they state they are willing to participate on it.

This consent involves informing the subjects about their rights, the procedures they will undergone to, the purpose of the study and the risks and benefits they might have. However, in this consent the researchers do not disclose the hypothesis of the study because this might put in risk the results of the study (since participants might change their behavior due to this).

Therefore, the correct answer is that informed consent means that b) subjects agree to participate in a study after receiving complete information about the nature and purpose of the study.