This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdomen & Pelvis, Subject name: Anatomy
[{'content': 'Choose the appropriate lettered structure in this computed tomography scan of the male perineum and pelvis. In which structure would ligation of the external iliac artery reduce blood pressure? \nSelect and explain. \nA. A, B. B, C. C, D. D', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (a) The external iliac artery becomes the femoral artery immediately after passing the inguinal ligament. Therefore, ligation of the external iliac artery reduces blood pressure in the femoral artery.', 'role': 'assistant'}]