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': 'The new drug pemetrexed useful in breast cancer belongs to which of the following category of the drugs ? \nSelect and explain. \nA. Antitumor agent, B. Alkylating agent, C. Hormonal agent, D. Antimetabolite', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]