Answer:
This best illustrates that creativity may be inhibited by D. extrinsic motivation.
Explanation:
Extrinsic motivation is an external motivation to the individual, it is a behavior which tends to be influenced by external factors or rewards.
In this case, Arlo's extrinsic motivation would be fame and fortune but it inhibits his creativity since as soon as he reminds himself that his musical skills could earn him these factors, he becomes less creative.
These external factors directly influence his creative decrease.
