Which sentence does not contain any punctuation errors?   A.Vegetables, fruits, and whole grains are healthful, but doughnuts, cake, and candy are not.  B.Vegetables, fruits, and whole grains are healthful; but doughnuts, cake, and candy are not.   C.Vegetables, fruits, and whole grains are healthful, doughnuts, cake, and candy are not.   D.Vegetables, fruits, and whole grains are healthful but doughnuts, cake, and candy are not.