The student guards in zimbardo’s stanford prison experiment behaved the way they did because: a. they were simply following orders from a legitimate authority figure, who in this case was their professor. b. they experienced the lucifer effect, in which they were affected by social surroundings and cultural expectations. c. they were malnourished. d. they believed the “inmates” had actually committed crimes and deserved punishment.

The correct answer is b. they experienced the Lucifer effect, in which they were affected by social surroundings and cultural expectations. 

The Lucifer Effect refers to the phenomenon in which particular situations and circumstances change "good" and moral individuals into immoral ones, capable of inflicting pain on others. In the Stanford Prison experiment, the student "guards'" harsh behavior towards the "prisoners'" can be explained in terms of the Lucifer effect, where the situation and circumstances at the time of the study affected the student guards' behavior.