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
A boy age 6 years, weight 13 kg. PEM grading 
Select and explain. 
A. Grade II, B. Grade I, C. Grade III, D. Grade IV
A: Grade II
Answer: A: Grade II 
Explanation: None