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': 'Shiga toxin acts by ? \nSelect and explain. \nA. Activating adenylyl cyclase to increase cAMP, B. Activating guanylyl cyclase to increase cGMP, C. Inhibiting protein synthesis, D. Inhibiting DNA replication', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Inhibiting protein synthesis", 'role': 'assistant'}]