Frasier Felt His Life Was Hopeless and Climbed Out onto a Bridge

Frasier felt his life was hopeless and climbed out onto a bridge deck, planning to commit suicide. Initially, about 40 people stood and pointed at him as he clung to the railing on the bridge, but after 30 minutes most of the crowd had dispersed. When only three people remained, one of the onlookers decided to call for help. The best explanation for why Frasier received help when the crowd was small, rather than when it was large, is that

A) diffusion of responsibility is less likely to occur in a small group.
B) group polarization is less likely to occur in small groups.
C) small groups tend to be less cohesive than larger groups.
D) cognitive dissonance decreases as the size of a group is decreased.