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': 'All except one is true regarding carotid sheath \nSelect and explain. \nA. Carotid sheath contains internal carotid artery, internal jugular vein, and vagus nerve, B. It is formed by investing layer of deep cervical fascia, pretracheal and prevertebral fascia, C. Sympathetic chain runs vertically through the carotid sheath, D. 9,11, and 12th cranial nerves pierce the upper part of carotid sheath', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sympathetic chain runs behind the carotid sheath.', 'role': 'assistant'}]