The recommended time for prophylactic antibiotic is:

Ans. (A) 30 min prior to induction of anesthesia(Ref: Katzung 11th/e p898)Antibiotic should be present in adequate concentration at the operative site before incision and throughout the procedure.Parenteral agents should be administered during the interval beginning 60 minutes before incision; administration up to the time of incision is preferred.