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
The antibiotic which acts by interfering with addition of new cell wall subunits (Muramyl pentapeptides) is: 
Select and explain. 
A. Bacitracin, B. Penicillins, C. Vancomycin, D. Mupirocin
C: Vancomycin
Answer: C: Vancomycin 
Explanation: Vancomycin, penicillin and bacitracin acts by inhibiting cell wall synthesis. Ref: Harrisons, Edition-18, Page : 1134.