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': 'A 45-year-old male, Sonu presented to OPD with severe pain in the knee and shoulder joint. On examination and further investigations, a diagnosis of rheumatoid arthritis was made and the patient was started on methotrexate 15mg weekly. However, even after 6 months of using methotrexate, recurrent episodes of arthritis continued. The physician wanted to add another DMARD that inhibit the pyrimidine synthesis by inhibiting dihydroorotate dehydrogenase enzyme. Which of the following drug, the physician is thinking about? \nSelect and explain. \nA. Sulfasalazine, B. Infliximab, C. Leflunomide, D. Abatacept', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]