This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti Microbial, Subject name: Pharmacology
Primaquine acts on which stage of life cycle of all human malarial parasites for causal prophylaxis? 
Select and explain. 
A. Pre erythrocyte, B. Erythrocyte, C. Exo erythrocyte, D. Hyponozoite
A: Pre erythrocyte
Answer: A: Pre erythrocyte 
Explanation: Ans. is 'a' i.e., Pre erythrocyte Antimalarial drugsPurpose Acting onExamplesCausal prophylaxisPreerythrocytic schizogony1. For falciparum: Proguanil, tetracycline2. For all species: PrimaquineClinical cure 1. Fast acting - Chloroquine, amadioquine, quinine, mefloquine, halofantrine, lumefanterine, atovaquone, artimisinin.2. Slow acting - Pyrimethamine, proguanil, sulfonamides, tetracyclines.GametocidalGametocytes1. For all species: Primaquine, artimisinins2. For P. vivax: Chloroquine, quinineRadical careExoerythrocytic schizogonyI. Primaquine