In Milgram's Obedience Experiments, "Teachers" Exhibited a Somewhat Lower Level

In Milgram's obedience experiments, "teachers" exhibited a somewhat lower level of compliance with an experimenter's orders when the

A) experiment was not associated with a prestigious institution like Yale University.
B) "learner" complained of a slight heart condition just before the experiment began.
C) "learner" screamed as the shocks became more punishing.
D) "learner" was in another room where his physical well-being couldn't be observed by the "teacher."