The correct answer is D. Testimonial
Step-by-step explanation:
In advertising, there are multiple techniques used to sell a product or convince the audience about one specif idea, in the case of the testimonial advertising technique, this uses a famous or a person that seems to be an authority in order to promote a product, mainly because this person recommends its use or give a testimony on the benefits or advantages of the product being promoted. This is a common technique to endorse products and widely used for cosmetics, drinks, and clothes. Considering this, it can be concluded the type of propaganda technique that involves a well-known person endorsing a product is "Testimonial".