The Bottom Line on Humor, According to Gass & Seiter

The bottom line on humor, according to Gass & Seiter, is

A) Humor rarely helps persuade people, and it often hinders persuasive efforts
B) Humor facilitates persuasion, but is less effective than most other types of appeals
C) Humor indirectly facilitates persuasion, but is no more effective than using evidence and reasoning
D) Humor enhances persuasion, but only when it is combined with other types of appeals