Rhetoric is the art of persuasion, which along with grammar and logic, is one of the three ancient arts of discourse. Rhetoric aims to study the techniques writers or speakers utilize to persuade, or motivate particular audiences in specific situations
This introductory passage does three main things: it gives the topic of the book (Answer A); it covers the contents of the book (Answer B); and it informs readers of what they will learn (Answer C). All these things are an important part of an introduction or overview.
