What Was the Outcome of the Classic Prison Simulation Done

What was the outcome of the classic prison simulation done by Zimbardo and his associates?

A) Without being told to do so, students playing the role of guards behaved sadistically toward the students in the role of prisoners.
B) When upper-class students were put in the role of prisoner, they were not abused as much as the working-class students in the same role.
C) The students acting in the roles of both prisoners and the prisoners did not take the experiment seriously and so it was discontinued early.
D) The findings were not significant in terms of how people adapt to roles of authority.