For all the intricacies of Vonnegut´s narrative, it could be said that most of his sci-fi pieces concern societal issues treated through science fiction and humor. This story is not the exception. In it, the main character, Barnhouse discovers he can manipulate physical objects and even events. He informs the government of his discoveries and is turned into a weapon. He rejects this role and uses his powers to destroy all military weapons. He passes this knowledge on to his student who is like minded.
The correct answer is D. Cannot stand as a sentence.
Subordinate clauses convey no meaning when left alone and must always be used in combination with independent clauses so as to create a complex sentence that conveys meaning.