Some of the most successful online advertising is unaided by advertising agencies or expensive marketing campaigns. (recall recent strategies for positioning movie releases, particularly in the horror film genre.) this type of advertising is known as

Viral advertising or viral marketing

Explanation:

Viral marketing or viral advertising occurs when a company uses social media platforms to advertise their products to the customers. The name viral comes from the fact that everyone who has social media account will see this advert and they will spread it like a virus as people will share it with others on the social media and it will go viral.

This kind of marketing is based on social media platforms where business people will put a video non You tube which get shared on other social networks and more people will share it.

If the message doesn't get misinterpreted because all the power is the hands of the social networks users it will bring the business many customers.

the correct answer is c.