A 26 year old man visits his psychiatrist for a follow up after starting a new medication two weeks ago. Physical examination is unremarkable but laboratory tests show marked depletion of polymorphonuclear leukocytes. Which of the following medications is most likely responsible for this lab finding ? A- Clozapine B- Haloperidol C- Phenelzine D- Chlorpromazine E- Fluoxetine Answer