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': 'Staph. aureus causes vomiting in 16-18 hours. The mechanism of action is - \nSelect and explain. \nA. Stimulation of cy AMP, B. Vagal stimulation, C. Stimulation of CyGMP, D. Acts through ganglioside GM receptor', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Vagal stimulation", 'role': 'assistant'}]