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
An elderly woman suffering from schizophrenia is on antipsychotic medication. She developed purposeless involuntary facial and limb movements, constant chewing and puffing of cheeks. Which of the following drugs is least likely to be involved in this side effect - 
Select and explain. 
A. Haloperidol, B. Clozapine, C. Fluphenazine, D. Loxapine
B: Clozapine
Answer: B: Clozapine 
Explanation: Purposeless involuntary facial and limb movements, constant chewing and puffing of checks suggest the diagnosis of tardive dyskinesia (an extrapyramidal side effect of antipsychotics).
Clozapine does not produce extrapyramidal side effects.