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: Pharmacology
Dose of which of the following antibiotic does not require alteration in renal failure ? 
Select and explain. 
A. Vancomycin, B. Ethambutol, C. Erythromycin, D. Metronidazole
C: Erythromycin
Answer: C: Erythromycin 
Explanation: None