Read the following excerpt from President John F. Kennedy's "We Choose to Go to the Moon" speech. Then, answer the question that follows.
… we meet in an hour of change and challenge, in a decade of hope and fear, in an age of both knowledge and ignorance. The greater our knowledge increases, the greater our ignorance unfolds.
Which rhetorical device does Kennedy use to support his argument?
a) Antithesis: he is using contrasting ideas to emphasize the uncertainty of space exploration
b) Irony: he is saying the opposite of what he means about space exploration
c) Rhetorical question: he is stating something about space exploration in the form of a question
d) Zeugma: he is using figurative language to emphasize a literal and figurative meaning