Final answer:
The correct answer is b. Attractiveness. Attractiveness is defined as an affection for the source as a result of the source's physical appearance, behavior, or other physical factors.
Step-by-step explanation:
The correct answer is b. Attractiveness. Attractiveness is defined as an affection for the source as a result of the source's physical appearance, behavior, or other physical factors. In the context of persuasive messages, speakers who are deemed as attractive are generally more persuasive than less attractive speakers. This principle is often utilized in advertising, where famous actors and athletes are used to promote products.