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: ENT
[{'content': 'Which aery is responsible for epistaxis after ligation of external carotid aery? \nSelect and explain. \nA. Ethmoidal aery, B. Greater palatine aery, C. Ascending pharyngeal aery, D. Superior labial aery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ethmoidal aery is a branch of internal carotid aery while rest of the aeries provided in the options are branches of external carotid aeries, thereby after ligation of external carotid aery, ethmoidal aery is the only aery which can cause epistaxis.', 'role': 'assistant'}]