Final answer:
Advertising is an argumentative form of communication designed to persuade, which must be carried by a medium, primarily functions to sell products, and generally requires source disclosure.
Step-by-step explanation:
When considering the aspects of advertising, one can identify that it is indeed an argumentative form of communication as it often aims to persuade the audience to take a particular action, such as purchasing a product. In contrast to being free, advertising is a paid form of communication and must be carried by some medium, whether it be television, radio, print, or online platforms. While it is not true that advertising is never used to sell products—quite the opposite, in fact—selling is its primary function. And finally, in terms of legal requirements, transparent advertising typically mandates that the source of the message is known to protect consumers and uphold truth in advertisements.