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: Anaesthesia
[{'content': 'Position for orotracheal intubation – \nSelect and explain. \nA. Extension of neck and atlanto-occipital joint, B. Extension of only neck, C. Flexion of neck only, D. Flexion of neck and extension of atlanto-occipital joint', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Optimal head neck for ET intubation is obtained by flexion of the neck and extension of the atlanto-occipital joint.', 'role': 'assistant'}]