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': 'Common source of staph in hospital : \nSelect and explain. \nA. IV fluids, B. Infective wounds, C. Instruments, D. Bed linen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: MC mode of spread of S. aureus infection is via hands of health care workers.\nS. aureus is MC cause of surgical wound infection and can cross infect wound of other patient too.\nMost effective mode of prevention of nosocomial S. aureus infection is hand washing.', 'role': 'assistant'}]