This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Psychiatry
Severe mental retardation means IQ in the range of 
Select and explain. 
A. 50-70, B. 35-50, C. 20-35, D. <20
C: 20-35
Answer: C: 20-35 
Explanation: ICD-10 Codes for Mental Retardation F70 Mild mental retardation IQ 50-69 F71 Moderate mental retardation IQ 35-49 F72 Severe mental retardation IQ 20-34 F73 Profound mental retardation IQ <20 Reference: Page No .3450 chap. 37 Intellectual Disability (Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 9th Edition)