This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2017, Subject name: Pharmacology
Mechanism of action of Pemetrexed is:- 
Select and explain. 
A. RNA synthesis inhibitor, B. Dihydrofolate reductase inhibitor, C. Dopamine agonist, D. Topoisomerase inhibitor
B: Dihydrofolate reductase inhibitor
Answer: B: Dihydrofolate reductase inhibitor 
Explanation: Dihydrofolate reductase Inhibitors Methotrexate Pralatrexate Pemetrexed PEMETREXED - used in mesothelioma D: Topoisomerase introduces negative coil's and aids in replication IRINOTECAN - topoisomerase Inhibitor