Answer: D) the use of united and divided.
Step-by-step explanation: Antithesis, which literally means “opposite,” is a rhetorical device that consists in putting together two opposite ideas to achieve a contrasting effect. In the given excerpt from John F. Kennedy’s Inaugural Address, we can see an example of antithesis in the sentences "United, there is little we cannot do in a host of cooperative ventures. Divided, there is little we can do—for we dare not meet a powerful challenge at odds and split asunder" because of the use of the opposite words "united" and "divided" to create contrast.