C

Causal prophylactic drugs (e.g., primaquine, tafenoquine, atovaquone-proguanil) prevent malaria by killing the early liver-stage parasites before they emerge into the bloodstream; these parasites are undergoing pre-erythrocytic (hepatic) schizogony, not the later blood or dormant stages [Mazier 2009 PMID 19876040; Flannery 2018 PMID 29321371].