Answer:
The answer is "Born but to die, and reasoning but to err."
Step-by-step explanation:
Antithesis is a rhetorical device employed to achieve a contrasting effect but putting together, in the same sentence, two opposite ideas. Antithesis uses word parallelism, meaning the contrasting words, phrases, or ideas present similar grammatical structures.
In the line "Born but to die, and reasoning but to err", we have two participles - a past participle and a present one - contrasted with two infinitive verbs. The ideas are opposed: "born" conveys the idea of starting one's life while "to die" conveys the idea of ending it; "reasoning" conveys the idea of thinking logically to choose right while "to err" means the wrong choice was made. Thus, that's the line that uses antithesis.