Final answer:
Handing out brochures at a convention for an upcoming product line constitutes direct marketing, as it is a personal and direct approach to encourage consumer response and transactions.
Step-by-step explanation:
An employee who works at a comics convention and hands out brochures to people passing by, promoting an upcoming product line and providing information on how to preorder these products, is engaging in direct marketing. This form of promotion is characterized by directly reaching consumers to generate a response or transaction. It involves a direct, personal approach to delivering information about a product or service, which in this case is the upcoming product line from a comic book company.