This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: ENT
[{'content': 'Tracheostomy indication is: \nSelect and explain. \nA. Vocal cord replacement, B. Pharynx replacement, C. Tracheomalacia, D. Foreign body obstructing airway', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Indications of tracheostomy: 1- Upper respiratory tract obstruction; Laryngeal, supralaryngeal ,and tracheal causes.( Causes of stridor ) 2- Lower respiratory tract obstruction: (Secretory obstruction, Wet lung syndrome). ref: hazarika 4th ed', 'role': 'assistant'}]