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
The new drug pemetrexed useful in breast cancer belongs to which of the following category of the drugs ? 
Select and explain. 
A. Antitumor agent, B. Alkylating agent, C. Hormonal agent, D. Antimetabolite
D: Antimetabolite
Answer: D: Antimetabolite 
Explanation: None