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: Surgery
[{'content': 'Delphian lymph nodes act as sentinal lymph nodes in: \nSelect and explain. \nA. Nasopharyngeal carcinoma, B. Laryngeal cancer, C. Parotid cancer, D. All of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Delphian lymph nodes are pretracheal / paratracheal lymph nodes which are sentiner lymph nodes in laryngeal cancer & thyroid cancer.', 'role': 'assistant'}]