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
Actinomycete is the source of which of the following anti microbials ? 
Select and explain. 
A. Tetracycline, B. Polyene, C. Aztreonam, D. Colistin
A: Tetracycline
Answer: A: Tetracycline 
Explanation: None