For Which One of the Following Individuals Is Behavior Clearly

Multiple Choice

For which one of the following individuals is behavior clearly affected by an incentive?

A) Alphonso gets wrapped up in a mystery novel and doesn't hear the doorbell ring.
B) Blake does several extra-credit projects to ensure his A in sociology.
C) Cecil smiles when his girlfriend gives him a new sweater.
D) Darren eats junk food even when he's not hungry.