Final answer:
Participants in Milgram's experiment were less likely to comply with authority when the repercussions of their actions were more directly observable, such as seeing the learner, or when authority was diminished. The direct answer choices provided in the question do not accurately represent this result; thus, the correct scenario is not listed among the options.
Step-by-step explanation:
Results of Milgram's experiment showed that participants were less likely to comply with the authority figure's requests when the humanity of the person being shocked was increased, or when the authority of the experimenter decreased. Several variations of the experiment confirmed these findings. For instance, when the teacher could see or had to touch the learner, obedience decreased. Moreover, when the commands were given via phone or when the setting was less prestigious, compliance also dropped.
To answer the question directly, participants were less likely to comply with the authority figure's requests when: b) the learner's responses were not visible. This is incorrect as the correct choice should be when the learner's responses were visible, or in a less authoritative setting, which are not provided options in the question.
Other findings from the experiment include that a significant majority of participants were willing to administer shocks because an authority figure instructed them to, even when the act conflicted with their conscience. This shows the powerful impact of authority on obedience.