This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Clinical diphtheria is caused by \nSelect and explain. \nA. Corynebacterium diphtheriae, B. Corynebacterium parvum, C. Corynebacterium Ulcerans, D. Streptococcus pyogenes', 'role': 'user'}, {'content': "Answer: A \nExplanation: Corynebacterium diphtheriae is the causative agent for diphtheria. The incubation period is 3-4 days. The site of infections is faucial, nasal, otitic, laryngeal, cutaneous. According to clinical severity, malignant, septic and hemorrhagic types are there. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 240", 'role': 'assistant'}]