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
Alirocumab and Evolocumab are: 
Select and explain. 
A. NPGL1 inhibitors, B. Microsomal transport protein inhibitors, C. PCSK - 9 inhibitors, D. Lipoprotein lipase inhibitors
C: PCSK - 9 inhibitors
Answer: C: PCSK - 9 inhibitors 
Explanation: PCSK - 9 expressed over many tissues which inhibits metabolism of LDL - receptors. Drugs like Alirocumab & Evolocumab inhibit PCSK - 9 and increased LDL - receptor turnover. Thus they decrease the levels of LDL.