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: Social & Preventive Medicine
[{'content': 'Each gram of fat supplies how many kcal of energy: \nSelect and explain. \nA. 5, B. 9, C. 12, D. 13', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The various nutrients provide energy as follows: Nutrient Energy in kcal/ gram Protein 4 Carbohydrate 4 Fat 9 Dietary Fibres 2 Ref: Park 21st Edition, Page 585.', 'role': 'assistant'}]