Answer:
D. Online marketing, social media marketing, and mobile marketing
Explanation:
Digital direct marketing is a fusion of <em>digital </em>and <em>direct </em>marketing. <em>Digital </em>includes online and mobile (smartphone) media, while the traditional media often refers to telephones, TV, brick-and-mortar shops...
Since the term <em>direct</em> refers to the way of approaching customers, it is important to make a distinction between marketing channels and media that are aimed for a wider public, and the ones that have the possibility of targeting a specific customer or target group.
The only answer that includes types of DDM (digital direct marketing) is <em>D</em>.
Online and social media marketing are tightly related and are digital by nature. They have the functionality to target customers directly with the aid of <em>cookies </em>and data provided by social media. Also, mobile marketing is direct and digital too, as it is related to smartphones and unique phone numbers (thus, it is direct).