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: Psychiatry
A person is said to be mentally retarded when IQ is 
Select and explain. 
A. < 100, B. <90, C. <80, D. <70
D: <70
Answer: D: <70 
Explanation: Normal IQ → 90-109;
Borderline IQ → 70-89;
Mild mental retardation IQ → 50-69;
Moderate mental retardation IQ → 35-49;
Severe MR IQ → 20-34;
Profound MR IQ → 0-19.