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': 'Which toxin is not mediated by cAMP \nSelect and explain. \nA. V. cholera 01, B. Heat stable E.coli toxin, C. Heat labile E.coli toxin, D. V.cholera 0137', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]