The answer is A: Violent delights.
An oxymoron is a figure of speech in which two apparently opposing terms are placed in conjunction. The two terms, though they would seem to contradict each other, are used as rhetorical device in order to make the reader ponder their conjunction, either as humorous device or as a technique to arouse wonder. In the answer above, delights would more likely be paired with terms such as, peaceful or graceful, but when placed next to violent, the sense of the word delights changes.