How Did Latané and Darley (1968)vary the Number of Bystanders

How did Latané and Darley (1968) vary the number of bystanders in their experimental study of the effects of the number of witnesses exposed to an emergency?

A) Participants who arrived first were assigned to a large group condition,and those who arrived later were assigned to a small group condition.
B) They randomly assigned participants to one of three conditions: large discussion group,small discussion group,or one-on-one discussion group.
C) They allowed participants to choose whether to participate in a group or in a one-on-one discussion.
D) They asked participants to wait in a hallway alone,or else with a group of others.
E) They randomly choose a number of different bystanders for each participant.