In saying, "not to strive after a life of ignoble ease, but to strive to do their duty," Roosevelt uses:

A. metaphor.********
B. simile.
C. antithesis.
D. allegory.
E. climax.

No.

Look up those terms here: http://literary-devices.com/

Let us know what you discover.

To determine how Roosevelt uses the literary device in the given statement, we can first understand what each of the options means.

A. Metaphor: a figure of speech that compares two unlike things without using "like" or "as."
B. Simile: a figure of speech that compares two unlike things using "like" or "as."
C. Antithesis: a literary device that uses contrasting words or concepts within parallel sentence structures.
D. Allegory: a form of narrative where characters and events represent abstract ideas or moral qualities.
E. Climax: the most intense, exciting, or significant point in a literary work.

Looking at the statement, "not to strive after a life of ignoble ease, but to strive to do their duty," Roosevelt contrasts two different ideas of what people should strive for. The use of the word "but" indicates a juxtaposition or contrast. This aligns with the definition of antithesis, as Roosevelt uses contrasting words (ignoble ease vs. doing their duty) within a parallel sentence structure.

Therefore, the correct answer is C. antithesis.