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': 'low tracheostomy is incision below \nSelect and explain. \nA. 2nd Tracheal ring, B. 3rd Tracheal ring, C. 4th Tracheal ring, D. 1st Tracheal ring', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]