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': 'Toxin production by corynebacterium diphtheriae is due to ? \nSelect and explain. \nA. Chromosomal mutation, B. Presence of plasmid, C. Lysogenic conversion, D. Transformation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]