A home security service provider hires a famous actor who plays a law enforcement officer in most of ...

A home security service provider hires a famous actor who plays a law enforcement officer in most of his movies to publicize its services. The company pays the actor for all his media appearances and advertisements where their brand is represented.
 
  What technique is used here, and why?
  a. Endorsement; celebrities add glamour and tend to attract viewers.
 b. Testimonial; to receive direct statements from celebrities as credible sources
 c. Persuasion; to persuade people to follow celebrity trends.
 d. Emotional appeal; persuasive messages move viewers and play with their emotions.