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: Medicine
[{'content': 'All of the following are features of mycobacterium tuberculosis, except : \nSelect and explain. \nA. Non spore forming, B. Aerobic bacterium, C. Measures 0.5-3 micon m, D. Gram stain as gram positive', 'role': 'user'}, {'content': 'Answer: D \nExplanation: M.Tuberculosis is often neutral on gram staining. Once stained it can be decolorised by acid alcohol. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 134', 'role': 'assistant'}]