The correct answer is C. Carter uses Hyperbole to make a connection between the past and the present in the sentence "We are the heirs of generations who survived threats much more powerful and awesome than those that challenge us now. Hyperbole makes an unrealistic comparison ob things, which is exemplified by the phrase much more powerful and awesome than.
He uses Anaphora to support his argument that America is strong because of its citizens in the phrase "We know the strength of America. We are strong. We can regain our unity. We can regain our confidence. Anaphora is a way of repetition, more specifically the repetition of the first part of the sentence which we can see in the repeated use of the word we.
The other options are not correct since option C is the only one that has a device that makes a comparison