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': 'Drug X is useful in the treatment of rheumatoid arthritis. It is available only in the parenteral formulation and its mechanism of action is antagonism of tumor necrosis factor. Which of the following can be X? \nSelect and explain. \nA. Cyclosporine, B. Penicillamine, C. Phenylbutazone, D. Etanercept', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]