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
[{'content': 'Amphotericin–B is obtained from : \nSelect and explain. \nA. Streptomyces nodosus, B. Streptomyces pimprina, C. Streptomyces nousseri, D. Streptomyces fragilis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]