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
Post - translation modification is seen with 
Select and explain. 
A. Streptomycin, B. Penicillin, C. Sulphonamides, D. Cephalosporins
A: Streptomycin
Answer: A: Streptomycin 
Explanation: None