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: Surgery
[{'content': 'In a post operative intensive care unit, five patients developed post-operative wound infection on the same wound. Which of the following is the best method to prevent cross infection among patients in the same ward? \nSelect and explain. \nA. Fumigate the ward, B. Practice proper hand washing, C. Disinfect the ward with sodium hypochlorite, D. Give antibiotics to all other patients in the ward', 'role': 'user'}, {'content': "Answer: B \nExplanation: Hand washing remains the single most impoant and effective method for preventing the spread of infectious disease. Ref: Reichel's Care of the Elderly: Clinical Aspects of Aging By Joseph J. Gallo, 5th Edition, Page 300; Harrison's Principles of Internal Medicine, 18th Edition, Page 1114.", 'role': 'assistant'}]