The correct answer is D.
In his autobiographical essay, Sorrentino uses an undestatement when he says he was won "some literary awards."
Right before this sentence, Sorrentino explains that his work has been included in anthologies in Spanish, English and other languages and has been translated to twelve different languages.
These are great acomplishments which not all writers are able to achieve; so, by saying that he has "won some literary awards," he is understating his success as a writer.