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
Mental retardation is defined when I.Q. is below : 
Select and explain. 
A. 90, B. 80, C. 70, D. 65
C: 70
Answer: C: 70 
Explanation: C i.e. 70