I would say that the correct answer is C). Since I cannot find the article that is missing in your question I would try to help you with my response.
Standard English is the most understandable way of writing and if the author is describing some important and serous information, they must be written with Standard English. Dialect is more hard for understanding.
Because with a novel, more people will read it and consider his ideas, instead of going straight to the government he tried changing the societies opinions.
The Oxford English Dictionary is best for finding the "Descriptive" meaning. This is the literal meaning, known also as denotative. It can also help you with figurative meanings, but it is not its primary purpose.
