This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of lipid, Subject name: Biochemistry
Which is a lipotropic factor? 
Select and explain. 
A. HDL, B. Insulin, C. Choline, D. Carnitine
C: Choline
Answer: C: Choline 
Explanation: Agents such as choline, methionine, Betaine, inositol, etc. which have the apparent effect of facilitating the removal of fat from liver, and thus prevents accumulation of fat in Liver cells. Such substances which prevent accumulation of fat in liver are said to be 'Lipotropic' ('Lipotropic agents' or 'Lipotropins'). The phenomenon itself is called "Lipotropism". Antagonistic agents and the converse condition are "anti-lipotropic" and "anti- lipotropism" respectively.Ref: Textbook of Medical Biochemistry, Eighth Edition Dr (Brig) MN Chatterjea, page no: 458