This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Targeted Anticancer Drugs and Immunosuppressants, Subject name: Pharmacology
Which of the following drugs used in the therapy of metastatic melanoma is a MEK inhibitor? 
Select and explain. 
A. Vemurafenib, B. Ipilimumab, C. Dabrafenib, D. Trametinib
D: Trametinib
Answer: D: Trametinib 
Explanation: MEK INHIBITORS: Trametinib, Binimetinib, Cobimetinib Reversible inhibitor of mitogen-activated extracellular signal regulated kinase (MEK). Used in the treatment of MALIGNANT MELANOMA Dabrafenib and vemurafenib are BRAF inhibitors used in MALIGNANT MELANOMA. Ipilimumab is a monoclonal antibody against CTLA-4. It is also approved for treatment of malignant melanoma.