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': 'Modified radical neck dissection type II \nSelect and explain. \nA. Removal of level I - V lymph nodes with only spinal accessory nerve, B. Removal of level I - V lymph nodes with sternocleidomastoid muscle, C. Removal of level I - V lymph nodes with spinal accessory nerve and internal jugular vein, D. Removal of level I - V lymph nodes with sternocleidomastoid muscle and internal jugular vein', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]