Nabila was at a busy grocery store when she and many others saw a gentleman on the ground. She stopped to stare and thought to herself that surely someone had already called for help for this man. She decided that because so many people were present to see the gentleman, help was already on the way. Nabila's decision not to call for help can be best explained by
a. groupthink.
b. the diffusion of responsibility.
c. social facilitation.
d. the fundamental attribution error.
Answer: b