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 child with schizophrenia was on medications. Suddenly he developed neck stiffness & spasm. What is most probable cause? 
Select and explain. 
A. Conversion disorder, B. Acute dystonia, C. Akathisia, D. Tardive dyskinesia
B: Acute dystonia
Answer: B: Acute dystonia 
Explanation: Ans. is'b'i.e., Acute dystonia[Ref: Kaplan & sadock's p 992