A post operative patient developed septicemia and was empirically started on combination chemotherapy by a new resident doctor.However,when the patient didnot respond even after 10 days of antibiotics treatment,the review of the charts was done.It was found that the resident doctor had started the combination of antibiotics which was metually antagonistic in action.Which one of the following is the most likely combination that was given?

• A. Cephalexin and Gentamicin
• B. Vancomycin and Amikacin
• C. Ciprofloxacin and Piperacillin
• D. Ampicillin and Chloramphenicol