This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
[{'content': 'The following anticancer drug is naturally obtained from plants? \nSelect and explain. \nA. Cisplatin, B. Tretinoin, C. Vincristine, D. Omalizumab', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Naturally obtained anticancer drugs are vinca alkaloids, taxanes, L-Asparginase, and camptothecins.Ref: Sharma and Sharma 3rd ed /Pg: 866', 'role': 'assistant'}]