This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concepts in physiology, Subject name: Physiology
[{'content': 'In a man with 45 kg of weight and 1.5 m of height, the BMI is: \nSelect and explain. \nA. 19, B. 20, C. 21, D. 22', 'role': 'user'}, {'content': 'Answer: B \nExplanation: BMI = Weight(kg)/ Height (m2) 45/2.25 = 20 Classification of adults according to BMI: Classification BMI Underweight < 18.50 Normal BMI 18.50-24.99 Overweight > 25 Pre-Obese 25-29.99 Obese Class 1 30.00 -34.99 Obese Class 2 35.00-39.99 Obese Class 3 > 40.00', 'role': 'assistant'}]