Concept:An oxymoron is a figure of speech in which two opposite or contradictory words are used together for emphasis or effect.
Explanation:Look closely at the expression "brave cowards".
The word "brave" means showing courage, while "coward" means lacking courage.
These two words contradict each other completely.
They are placed side by side in the same phrase to create a striking effect.
This direct pairing of opposites is the defining feature of an oxymoron.
Irony would require a wider contrast between what is said and what is meant.
Antithesis sets opposing ideas in parallel structures, not in a single compressed phrase.
A eulogy is a formal speech praising someone who has died.
None of those other devices matches the structure of "brave cowards".
Answer:D. Oxymoron