Read this line from "do not go gentle into that good night."

"grave men, near death"

which best identified the figurative device?

a. pun
b. oxymoron
c. alliteration
d. hyperbole

The answer is A, pun.
Hyperboles are sayings that aren't meant to be taken literally.
Oxymorons are figures of speech that contradict each other ex: living dead, alone together. 
Alliteration is an occurrence of the same letter or sound at the beginning of closely connected words.
and i think we all know what puns are. 
it's a pretty prosaic pun