Which activity involves paying for media space or time to promote specific goods or services?

The activity of paying for media space or time to promote specific goods or services is known as advertising. Advertising is a key component of marketing that involves creating awareness and interest in a product or service through various channels such as television, radio, print, and digital platforms. By purchasing placement in these media venues, businesses are able to reach a wider audience and effectively communicate their messages to potential consumers.

In contrast, public relations focuses on building and maintaining a positive image and relationship with the public without direct payment for media placement. Promotional campaigns may include various strategies, including discounts or sales events, but do not specifically denote the act of purchasing advertising space. Market research, on the other hand, involves gathering data about consumer preferences and behaviors to inform marketing strategies and does not involve promoting products directly. This distinction highlights why advertising is the correct answer.