Sixty-Five Percent of the Research Participants in Milgram's Study Believed

Sixty-five percent of the research participants in Milgram's study believed they administered maximum (dangerous) levels of electric shock to a stranger. Which of the following groups of participants did the 65 percent form?

A) people who were in the same room as a victim whom they could see and hear
B) people who were in a different room from a victim whom they could see and hear
C) people who were in a different room from a victim whom they could see but not hear
D) people who were in a different room from a victim whom they could neither see nor hear