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': 'An antibiotic not acting on tubulin is ? \nSelect and explain. \nA. Bleomycin, B. Colchicine, C. Paclitaxel, D. Vincristine', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Bleomycin Bleomycin (an anticancer antibiotic) does not act on tubulin.", 'role': 'assistant'}]