Final answer:
Frank Pepe's Pizzeria's charity donation during "good neighbor night" is part of the promotion mix, specifically the public relations efforts. This strategy aims to build goodwill and enhance the company's image in the community.
Step-by-step explanation:
The activity that Frank Pepe's Pizzeria is conducting, known as "good neighbor night", where they donate 15 percent of their proceeds to charity, can be categorized under the promotion mix element of public relations within a company's marketing strategy.
Public relations activities are designed to promote goodwill amongst the community and enhance the company's image. By supporting a charity, the pizzeria not only gives back to the community but also builds a positive reputation which can lead to increased customer loyalty and brand awareness.