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': 'Corynebacterum other than diphtheriae carrying toxin: \nSelect and explain. \nA. Corynebacterium ulcerans, B. Corynebacterium xerosis, C. Corynebacterium striatum, D. Corynebacterium urealyticum', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is. 'a' i. e. Corynebacterium ulcerans", 'role': 'assistant'}]