It would be proofreading ( c ) to see if what you wrote moves the story forward and the dialogue is correct, and any grammar commas and other punctuation are correct.
So ppl can express their opinions on issue
It means they are taking a trip on the budget
The question is a little ambiguous - The best definition of tone in writing would be your attitude towards your subject as revealed through your word choice. The best definition on the given list, however, is probably D, as your purpose is generally related to your attitude towards your subject.