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': 'All are true regarding diphtheria toxin except - \nSelect and explain. \nA. Toxin blocks elongation of protein, B. Beta lysogenic strain produces toxin, C. Iron is critical for toxin production, D. Toxin is necessary for local wound production', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]