This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy: General Principles, Subject name: Pharmacology
[{'content': 'Gemcitabine is effective in: \nSelect and explain. \nA. Head and neck cancers, B. Pancreatic cancer, C. Small-cell lung cancer, D. Soft tissue sarcoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (B) Pancreatic cancer(Ref: Katzung 10th/e p891, KDT 8th/e p924)Gemcitabine is an antimetabolite that is the drug of choice for pancreatic cancers.', 'role': 'assistant'}]