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': 'Ipilimumab is monoclonal antibody against : \nSelect and explain. \nA. PD - L1, B. CTLA - 4, C. CD - 52, D. IL - 4', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ipilimumab is monoclonal antibody against CTLA-4 used in the treatment of Metastatic Melanoma.', 'role': 'assistant'}]