This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parasitology Pa 1 (Protozoology), Subject name: Microbiology
[{'content': '30 yrs old farmer treated initially with chloroquine for uncomplicated malaria now has an episode of relapse, what could be the reason for relapse? \nSelect and explain. \nA. P. vivax has a significant level of chloroquine resistance., B. P. vivax has a persistent exoerythrocytic stage (hypnozoite)., C. P. vivax has a persistent erythrocytic stage., D. Chloroquine is not one of the drugs of choice.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Both Plasmodium ovale and Plasmodium vivax may have resting liver forms, which are very slow to develop into schizonts with merozoites and proceed onto the chloroquine-sensitive erythrocytic stages after treatment is over.', 'role': 'assistant'}]