72.長期洗腎病患突然解血便,在急診室曾發生休克,緊急血管攝影檢查(下腸繫膜動脈,inferior mesenteric artery),如圖,箭號所指之腸出血最可能源自下列那一條血管? (A)internal pudendal artery (B)superior rectal artery (C)inferior gluteal artery (D)superior vesical artery