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: Pediatrics
A 3 year old boy with normal developmental milestones with delayed speech and difficulty in communication and concentration. He is not making friends. Most probable diagnosis is – 
Select and explain. 
A. Autism, B. ADHD, C. Mental retardation, D. Specific learning disability
A: Autism
Answer: A: Autism 
Explanation: Delayed speech, difficulty in communication and concentration in a 3 year old child suggests the diagnosis of autism.
Autism

Autism is a neurologic disroder characterized by -


Qualitative impairment in social interaction
Qualitative impairment in communication.
Restricted repetitive and streotyped patterns of behaviour, interests, and activities.