This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Membrane Structure & Function, Subject name: Biochemistry
Which of the following is the major proteoglycan of synovial fluid - 
Select and explain. 
A. Chondroitin sulfate, B. Dermatan sulfate, C. Heparan sulfate, D. Hyaluronic acid
D: Hyaluronic acid
Answer: D: Hyaluronic acid 
Explanation: Ans. is 'd' i.e., Hyaluronic acid DistributionHyaluronic acido Synovial fluid (provides viscosity), vitreous humor, loose connective tissue)Chondroitin sulfateo Cartilage, bone, tendon, ligament, corneaDermatan sulfateo Pliability of skin, and heart valves, wide distributionKeratan sulfateo Homy structures like hair, nails, claws, horn, hoofso Also present in corneaHeparino Mast cellsHeparan sulfateo Skin fibroblast, aortic wall