Which of the following is correct about the transverse section of a vein, when compared with that of an
artery?

• A.The lumen of a vein is wider than that of an artery
• B.The endothelium of the vein is thinner than that of an artery
• C.There are more smooth muscles in a vein than in an artery
• D.There are valves in veins but not in arteries.