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': 'About vinca alkaloids true is ? \nSelect and explain. \nA. Inhibits mitotic spindle, B. Enhances polymerization of tubulin, C. Inhibits topoisomerase I, D. Inhibits topoisomerase II', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Inhibits mitotic spindle Vinca alkaloids (vincristine) inhibit mitotic spindles by preventing polymerization of tubulin", 'role': 'assistant'}]