Problem: What is the most effective timing of a specific antibiotic during preparation of the patient for elective colectomy? Need Assignment Help? a. A single preoperative dose and 24 hours postoperative dose b. A single preoperative dose and 48 hours postoperative dose c. A single dose given within 30 minutes prior to skin incision d. A single dose at the time of incision. e. A single dose 24 hours postoperative.