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: Biochemistry
Platelet-activating factor is biochemically a 
Select and explain. 
A. Prostaglandin, B. Glycolipid, C. Glycerol ether phospholipid, D. Leukotrienes
C: Glycerol ether phospholipid
Answer: C: Glycerol ether phospholipid 
Explanation: Platelet-activating factor (PAF) (I-alkyl-2-acetyl-sn-glycerol-3- phosphocholine) is synthesized from the corresponding 3-phosphocholine derivatives. It is formed by many blood cells and other tissues and aggregates platelets at concentrations as low as 10 mol/L.