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 16 year old male is found to have a mental age of 9 years on I.Q. testing. He has: 
Select and explain. 
A. Mild Mental Retardation, B. Moderate Mental Retardation, C. Severe Mental Retardation, D. Profound Mental Retardation
A: Mild Mental Retardation
Answer: A: Mild Mental Retardation 
Explanation: A i.e. Mild Mental Retardation