What Was the Major Finding in Cialdini's (1978) Classic Study

What was the major finding in Cialdini's (1978) classic study on the lowballing technique?

A) Participants who were asked to sign up for a study, and then asked if they could come at 7 a.m., were more likely to attend than participants who were first told the study started at 7 a.m.
B) Participants who were first told that a study started at 7 a.m. were more likely to attend than participants who were asked to sign up before they knew the time of the study.
C) Participants were more likely to attend a later study if they first agreed to sign a form for the experimenter.
D) Participants were more likely to sign a form for an experimenter if they had first been asked to participate in a later study.