This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fundamental Concepts, Subject name: Anaesthesia
[{'content': 'The physiological dead space is decreased by: \nSelect and explain. \nA. Upright position, B. Positive pressure ventilation, C. Neck flexion, D. Emphysema', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Neck flexion FactorEffectPosture UprightincreaseSupinedecreasePosition of airway Neck extensionincreaseNeck flexiondecreaseAgeincreaseArtificial airwaydecreasePositive pressure ventilationincreaseAnticholinergic drugsincreasePulmonary perfusion Pulmonary emboliincreaseHypotensionincreaseEmphysemaincrease Factors affecting dead space.", 'role': 'assistant'}]