Yes that is correct, everything else is related to anger
hope that helps :)
Communication is somehow incomplete without writing. Writing is a second form of information therefore the two play important roles in working together; and these two are found inside language.
The rule of language affects communication because without it there won't be any communication. Language is the pivot upon which every communication rotates. Even the disabled (Deaf and Dumb), uses a language method in communication thereby proving how important it is for a message to be passed through communication.
C is the right one. Unlike quotations or paraphrased ideas, information that's considered "common knowledge" doesn't need to be cited. "Common knowledge" is information that's considered widely known or easily verified.