Refer to the figure above and then answer the question that follows.
-Insulin is a protein made in large amounts in cells of the pancreas. These cells secrete insulin into the blood, where it controls the uptake of sugar by body cells. How is insulin transported from the ER to the surface of the cell?

A) It is sent through the cavities (lumen) of the endoplasmic reticulum that attach directly to the plasma membrane.
B) It moves along tracks of cytoskeleton proteins.
C) It moves through plasmodesmata to the surface of the cell.
D) It is carried in small sacs of membrane (vesicles) that move from the endoplasmic reticulum to the Golgi apparatus and then to the plasma membrane.
E) It is carried by lysosomes that empty their contents outside the cell.