Ans. is 'b' ie. Proper hand washing of all ward personnel's "Given the prominence of cross infection, hand washing is the single most important preventive measure in the hospital" - Harrison 15/eHarrison 17/e writes- "Given the prominence of cross-infection, hand hygiene is the single most important preventive measure in hospitals. Use of alcohol hand rubs between patient contacts is now recommended for all health care workers except when the hands are visibly soiled, in which case washing with soap and water is still required"