This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Anatomy
Hypersensitivity vasculitis usually involve 
Select and explain. 
A. Aerioles, B. Post capillary venules, C. Capillaries, D. Medium sized aeries
B: Post capillary venules
Answer: B: Post capillary venules 
Explanation: Refer robbins 9/e p510, 8/e 515 Harrison 7/2128 Direct quote from Harrison 18th /2798; Postcapillary venules are most commonly involved vessels. Capillaries and aerioles are less frequent involved