This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cytotoxic Anticancer Drugs, Subject name: Pharmacology
[{'content': 'Vinca alkaloids act on which phase of cell cycle? \nSelect and explain. \nA. G1 phase, B. S phase, C. G2 phase, D. M phase', 'role': 'user'}, {'content': 'Answer: D \nExplanation: S phase specific drugs:- Antimetabolite - antifolate, purine, pyrimidine analogues M phase specific drugs:- Vinca alkaloids Taxanes Anti microtubule inhibitors', 'role': 'assistant'}]