Hypersensitivity vasculitis is seen most commonly in -: (A) Post capillary venules, (B) Arterioles, (C) Veins, (D) Capillaries
Answer is A. Pathology hypersensitivity vasculitis 

In hypersensitivity vasuculitis, postcapillary venules are the most commonly involved vessels, capillaries and arterioles are involved less frequently.
It is primarily a disease of small vessels.
It is characterized by leukocytoclasis, a term that refers to the nuclear debris remaining from the neutrophils that have infiltrated in and around the vessels during the acute stages.