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 true regarding anthrax ? \nSelect and explain. \nA. M' Fadyean reaction shows capsule, B. Humans are usually resistant to infection, C. Less than 100 spores can cause pulmonary infection, D. All", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is \'a\' i.e., M\' Fadyean reaction shows capsule; \'b\' i.e., Humans are usually resistant to infection; \'c\' i.e., Less than 100 spores can cause pulmonary infection . M\' Fadyean\'s reaction represents the capsular material and is characteristic of the anthrax bacillus. . "Man is relatively resistant to infection with B. anthracis". - Green wood 16th/e 226 . In animal studies, it has been shown that aerosolized anthrax -- 10,000 spores required to produce lethal disease. However, it has been suggested that as few as one to three spores may be adequate to cause disease in some setting. - Harrison 17thie 1344 . Spores are of same width as the bacillary body so that they do not cause bulging of the vegetative cell (in contrast the clostridia have bulging spores). . For laboratory diagnosis, specimens to be examined are fluid or pus from a local lesion, blood or sputum. Stained smears often show chains of large gram positive rods.', 'role': 'assistant'}]