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 3 year old girl with normal developmental milestones except that she staed speaking by the age of four. She does not play with other children and wants to eat, play and sleep in her own way. She often has temper tantrums related to any new changes. What is the likely diagnosis? 
Select and explain. 
A. ADHD, B. Autism, C. Specific learning disorder, D. Mental retardation
B: Autism
Answer: B: Autism 
Explanation: Autism is charecterised by a developmental delay in speech, communication difficulties, lack of social skills, difficulty in coping with change, rigid preferences and routines which is pervasive and persistent from childhood.