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: Pharmacology
[{'content': 'Most important factor for calculating dose for NSAIDS in children? \nSelect and explain. \nA. Age of child, B. Body weight of child, C. Flavour of salt, D. Extent of pain', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]