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': 'Anatomical dead space is increased by all /except \nSelect and explain. \nA. Atropine, B. Halothane, C. Massive pleural effusion, D. Inspiration', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Massive Pleural effusion - Pleural effusion normally tends to decrease physiological dead space initially. However when massive it also decreases anatomical dead space. Atropine, halothane are bronchodialators, so T anatomical dead space. Inspiration may also streatch airways to anatomical dead space.', 'role': 'assistant'}]