An Important Difference Between Asch's Experiment in Which Participants Judged

An important difference between Asch's experiment in which participants judged the length of lines and Sherif's experiment in which participants judged the movement of light was that

A) asch\s participants were older than were sherif\s
B) there was an obviously correct answer in judging the length of lines but that was not so in judging the movement of light
C) asch\s participants made their judgments privately whereas sherif\s participants made their judgments publicly
D) asch\s participants were all male whereas sherif\s participants were both male