The answer is A. These are the most updated guidelines for ANC monitoring (released in October 2015). Rechallenge is not absolutely contraindicated and can be considered after a risk-benefit discussion, although approximately one-third of patients may experience a repeat (and more severe) dyscrasia. Filgrastim is best reserved for short term use. Older patients and patients with a lower ANC at clozapine initiation appear to be at higher risk of agranulocytosis. The absolute risk of agranulocytosis with clozapine is 0.8%, and 2.9% for neutropenia.

Publication reference : Daniel JS and Gross T. Managing clozapine-induced neutropenia and agranulocytosis. Current Psychiatry 2016; 15: 51-53
Reference URL: https://www.clozapinerems.com/CpmgClozapineUI/rems/pdf/resources/Clozapine_REMS_HCP_Guide.pdf