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: Anatomy
[{'content': 'Carotid sheath encloses all except \nSelect and explain. \nA. CCA and ICA., B. ECA and  ICA., C. Internal jugular vein, D. Vagus nerve.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]