How Did Asch Induce Conformity in His Studies Involving Judgments

How did Asch induce conformity in his studies involving judgments of line length?

A) An authority figure urged participants to select a certain line.
B) Participants discussed the problem and came to a group consensus.
C) An attractive confederate of the opposite sex persuaded the participants.
D) Several accomplices gave incorrect answers before the true participant answered.