Has the Research on the Principle of Social Proof Shown

has the research on the principle of social proof shown?

A) It works best when the proof is provided by the actions of many other people.
B) It isn't strong enough to overcome deep-seated fears or phobias.
C) It works on adults but not children.
D) Live demonstrations of others' behavior are necessary for the effect to work; film clips don't produce good results.