A commercial that claims that OptiClean is the best toothpaste is the best example of rhetoric in action. Rhetoric is the art of using language to persuade and influence others, and the commercial is using persuasive language to convince the audience that OptiClean is the best toothpaste. The language used in the commercial is carefully chosen to appeal to the audience's desire for clean, healthy teeth, and to convince them that OptiClean is the best way to achieve that.