This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intellectual disability, communication, autism, and ADHD, 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: Ans. is 'd' i.e., < 70 o Normal IQ- 90-109;o Borderline IQ- 70-89;o Mild mental retardation IQ- 50-69;o Moderate mental retardation IQ- 35-49;o Severe MR IQ- 20-34;o Profound MR IQ- 0-19.