This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Airway, Subject name: Anaesthesia
[{'content': 'All true about armoured endotracheal tube except \nSelect and explain. \nA. These are tube with metal wire coil embedded in the wall of the tube shaft., B. It has radiopaque line like normal ETT, C. It is bend resistant, D. It has slightly thicker outer wall as compared to normal ETT', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Just likestandard ET tubes,armored or reinforced tubes have the typical left-facing bevel tip and Murphy eye. Their distinctive feature is ametal wire coilembedded in the wall of the tube shaft. The fact that these tubes contain a metal wire coil means there is no need for a radio-opaque line. Useful in head and neck surgeriesand when the patient is in a prone position.', 'role': 'assistant'}]