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
Ipilimumab is monoclonal antibody against : 
Select and explain. 
A. PD - L1, B. CTLA - 4, C. CD - 52, D. IL - 4
B: CTLA - 4
Answer: B: CTLA - 4 
Explanation: Ipilimumab is monoclonal antibody against CTLA-4 used in the treatment of Metastatic Melanoma.