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: Microbiology
[{'content': 'Which of the following is the commonest cause of malaria in the world? \nSelect and explain. \nA. P. vivax, B. P. ovale, C. P. falciparum, D. P. malariae', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Malaria has a worldwide distribution between 45degN and 40degS latitude, generally at altitudes below 1800 m. P vivax is the most widely distributed of the four species, and together with the uncommon P malariae, is found primarily in temperate and subtropical areas. P falciparum is the dominant organism of the tropics. P ovale is rare and found principally in Africa. Ref: Ray C.G., Ryan K.J. (2010). Chapter 50. Sporozoa. In C.G. Ray, K.J. Ryan (Eds), Sherris Medical Microbiology, 5e.', 'role': 'assistant'}]