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': 'Which of the following is contraindicated during endotracheal intubation: March 2011 \nSelect and explain. \nA. Head elevation, B. Preoxygenation with 100% oxygen, C. Introduction of blade toward the right side of oropharynx, D. Neck flexion at atlanto-occipital joint', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: Neck flexion at atlanto-occipital joint Technique of intubation includes: Patient should be supine and there should be extension at the Atlanto-occipital joint and flexion at the cervical spine', 'role': 'assistant'}]