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': 'Etanercept used in rheumatoid arthritis act by the inhibition of : \nSelect and explain. \nA. TNF alpha, B. TFG beta, C. IL–2, D. IL–6', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]