This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Surgery
[{'content': 'An 85-year-old hypertensive man is evaluated in the emergency department for recent onset epistaxis. His blood pressure is 150/80 mm Hg, and hematocrit is 39%. What is the most likely source of bleeding? \nSelect and explain. \nA. Posterior nasal septum, B. Anterior nasal septum, C. Inferior turbinate, D. Middle turbinate', 'role': 'user'}, {'content': "Answer: A \nExplanation: Epistaxis in children and young adults usually arises from the anterior nasal septum (Kiessel bach's plexus). In elderly persons, however, spontaneous rupture of a sclerotic blood vessel in the posterior nasal septum is usually the cause of bleeding, especially in combination with hypertension.", 'role': 'assistant'}]