This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organic Mental Disorder, Subject name: Psychiatry
IQ of 15 is which grade of mental retardation - 
Select and explain. 
A. Mild, B. Moderate, C. Borderline, D. Profound
D: Profound
Answer: D: Profound 
Explanation: Ans. is 'd' i.e., ProfoundCategoryIQNormal intelligence> 90Borderline intelligence70 - 89Mental retardationMild MR50 - 69Moderate MR35-49Severe MR20-34Profound MR0-19