Participants in Stanley Milgram's Obedience Experiments Found Themselves Caught Between

Participants in Stanley Milgram's obedience experiments found themselves caught between two norms: "obey legitimate authorities" and "do not inflict needless harm." According to the text,why was it especially difficult for participants to abandon the "obey authority" norm in favor of the "do no harm" norm?

A) The experimenter was in the same room and was a more salient normative stimulus than was the learner.
B) Participants were concerned they would lose the rewards they were promised for participating if they did not continue.
C) Task distractions and the fast pace made it difficult to decide that the "obey authority" norm was no longer appropriate.
D) Many participants had served in the military and had internalized the "obey authority" norm.
E) Participants were more concerned about how the experimenter would evaluate them than with how the learner would.