Which statement is an example of big-picture feedback?

A. "It might be a good idea to read your paper out loud; you have several verb use errors that need to be fixed."
B. "Your sentences are interesting, but many of them are short and choppy; be sure to vary the length of your sentences."
C. "You have a lot of run-on sentences in your essay; be sure to fix those and any other grammar issues in your next draft."
D. "You offer great evidence in your essay but I'm not sure what your argument is; make sure that is clear to the reader."