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: Forensic Medicine
Severe mental retardation is: NEET 13 
Select and explain. 
A. 50-70, B. 35-50, C. 20-35, D. < 20
C: 20-35
Answer: C: 20-35 
Explanation: Ans. 20-35