This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Lipids, Subject name: Biochemistry
Which decreases risk of coronary artery disease? 
Select and explain. 
A. LDL, B. HDL, C. VLDL, D. IDL
B: HDL
Answer: B: HDL 
Explanation: Ans. is 'b' i.e., HDL* High Density lipoprotein is involved in reverse cholesterol transport.* It collects cholesterol and phospholipids from extrahepatic tissue membranes and reach liver. In other words, it reverses atherosclerotic changes. Hence it is found to be protective against atherosclerosis.