This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Platelet, Subject name: Pathology
Blood group antigens chemically are made up of ? 
Select and explain. 
A. Carbohydrate, B. Glycoprotein, C. Phospholipids, D. Polysaccharide
B: Glycoprotein
Answer: B: Glycoprotein 
Explanation: Blood group antigens (ABO) Made up of glycoproteins. Expressed on the surface of RBCs and Platelets.