This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cholesterol synthesis and bile acids, Subject name: Biochemistry
HDL was called good cholesterol because: 
Select and explain. 
A. Activates lipoprotein lipase, B. Stimulate hepatic TGs synthesis, C. Causes transpo from extrahepatic tissues, D. Removes cholesterol from extrahepatic tissues
D: Removes cholesterol from extrahepatic tissues
Answer: D: Removes cholesterol from extrahepatic tissues 
Explanation: HDL Good and Bad cholesterol terminology was used earlier. Now these terms 'good' & 'bad' cholesterol are discarded. HDL was called good cholesterol because of reverse cholesterol transpo i.e. it takes cholesterol from peripheral tissue to liver. HDL conves this cholesterol into cholesterol ester with the help of enzyme LCAT-Lecithin Cholesterol Acyl Transferase. This enzyme transfers fatty acid from lecithin (a phospholipid) to cholesterol. Lecithin after losing fatty acid becomes lysolecithin (See fig below).