This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Hypersensitivity vasculitis affects 
Select and explain. 
A. Post-capillary venules, B. Aerioles, C. Veins, D. Medium-sized aeries
A: Post-capillary venules
Answer: A: Post-capillary venules 
Explanation: . Post-capillary venules