Which sentence uses a pair of antonyms?

a. because the ship was so enormous, our cabin was also quite large.
b. we spent the day drifting on the peaceful lake, feeling very calm.
c. the nervous speaker began with a whisper but finished with a roar.
d. the turtle’s protective shell keeps it safe from many of nature’s threats.
(i know it is either c or d)

Brutus: but as he was ambitious, i slew him. . who is here so base that would be a bondman? if any, speak, for him have i offended. who is here so rude that would not be a roman? if any, speak, for him have i offended. who is here so vile that will not love his country? if any, speak, for him have i offended. i pause for a reply. which rhetorical device does brutus use in this excerpt?