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: Social & Preventive Medicine
Chronological age 10 years, mental age 4 years. What that person called as? 
Select and explain. 
A. Idiot, B. Imbecile, C. Normal, D. Genius
B: Imbecile
Answer: B: Imbecile 
Explanation: IQ of this child = 4/10 x 100 = 40
Imbecile child has IQ between 25-49.