6. A type of cell called the lymphocytes makes proteins that are exported from the cell. You can track the path of these proteins by using pulse-chase experiment with radioisotope-labeled proteins to demonstrate the classic secretory pathway in cells. Which of the following might be the classic secretory pathway for those polypeptides to be sorted out?

(A) rough ER -- lysosome --- plasma membrane

(B) smooth ER -- Golgi --- plasma membrane

(C) nucleus -- rough ER -- Golgi --- plasma membrane

(D) rough ER -- Golgi --- plasma membrane

(E) rough ER --- mitochondria -- Golgi --- plasma membrane