Answer:
E. viral
Explanation:
Viral marketing, also known as viral advertising is a kind of the business strategy which uses the existing social networks in an organization to promote a particular product.
Like virus spreads from one person to the another, this type of marketing strategy follows same tangent in which the consumers spread the information about the product with the other people who are in their social networks. The mode of delivery can be via mouth or by internet and social media platforms.
Hence, the given example is kind of viral marketing.
