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': "True about corynebacterium diphtheriae is all except- \nSelect and explain. \nA. Deep invasion is not seen, B. Elek's test is done for toxigenicity, C. Metachromatic granules are seen, D. Toxigenicity is mediated by chromosomal change", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]