According to the APA's Ethics Code for Humans, Those Who

Multiple Choice

According to the APA's ethics code for humans, those who volunteer for a study

A) can quit at any time, without penalty
B) must be debriefed at the end of the study, if they request it
C) must sign an informed consent form that fully explains all aspects of the study ahead of time, including its complete hypothesis
D) must complete the study, once they begin