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': 'A boy age 6 years, weight 13 kg. PEM grading \nSelect and explain. \nA. Grade II, B. Grade I, C. Grade III, D. Grade IV', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]