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': "Cholera toxin acts by - \nSelect and explain. \nA. Na ATPase inhibition, B. Adenylate cyclase stimulation, C. Opening of chloride channel, D. Stimulation of Ca' channel", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is `b' i.e., Adenylate cyclase stimulation", 'role': 'assistant'}]