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
Which is the drug of choice for malaria in a 26-year-old pregnant lady, in the first trimester? 
Select and explain. 
A. Proguanil, B. Chloroquine, C. Aemesin, D. Halofantarine
B: Chloroquine
Answer: B: Chloroquine 
Explanation: Chloroquine is the drug of choice for prophylaxis and treatment of malaria during all phases of pregnancy. Chloroquine is a rapidly acting blood schizonticide which destroys asexual blood forms of all plasmodium species. For woman with chloroquine-resistant infection, mefloquine is given orally.