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: Medicine
In a post operative intensive care unit, five patients
developed post-operative wound infection on the same wound. The best method to prevent cross infection occurring in other patients in the same ward is to: 
Select and explain. 
A. Give antibiotics to all other patients in the ward, B. Fumigate the ward, C. Disinfect the ward with sodium hypochlorite, D. Practice proper hand washing
D: Practice proper hand washing
Answer: D: Practice proper hand washing 
Explanation: None