A patient with a history of schizophrenia presents with a compliant of fever, chills, productive cough and muscle aches for the past 2 days. She has tried anti-psychotic drugs in the past, and she recently began a new medication to treat her schizophrenia. On physical exam she is diaphoretic, and auscultation of her chest indicates decreased air entry in the right lower lob. Blood tests reveals profound leukopenia and an absolute neutrophil count of fewer thatn 300 cell/mm. Which of the following is most likely responsible for the abnormal lab finding?
1) Haldol
2) Lithium
3) Olanzapine
4) Clozapine