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
Red man syndrome is due to ? 
Select and explain. 
A. Vancomycin, B. Polymyxin, C. Rifampicin, D. Teicoplanin
A: Vancomycin
Answer: A: Vancomycin 
Explanation: None