This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
All are true regarding chloroquine, except ? 
Select and explain. 
A. Acts only on exo erythrocytic cycle, B. Acts on DNA and RNA of parasite, C. Causes pigmentation of nail and mucosa, D. Infected RBC has more drug
A: Acts only on exo erythrocytic cycle
Answer: A: Acts only on exo erythrocytic cycle 
Explanation: Ans. is 'a' i.e., Acts only on exoerythrocytic cycle o It is a rabidly acting erythrocytic Schizontacide against all species of plasmodium. o It has no effect on pre and exoerythric stage.