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': "The term 'animalcules' to oral microorganisms is given by: \nSelect and explain. \nA. W D Miller, B. Leeuwenhoek, C. Robertson, D. Socransky", 'role': 'user'}, {'content': "Answer: B \nExplanation: Animalcule ('little animal', from Latin animal + the diminutive suffix -culum) is an old term for microscopic organisms that included bacteria, protozoans, and very small animals.\xa0\nThe word was invented by Antonie van Leeuwenhoek to refer to the microorganisms he observed in rainwater.", 'role': 'assistant'}]