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: Physiology
Which of the following is the major constituent of the lung surfactant? 
Select and explain. 
A. Mucoprotein, B. Phospholipids, C. Fibrinogen, D. Fibrin
B: Phospholipids
Answer: B: Phospholipids 
Explanation: Nearly 77% of surfactant is composed of phospholipids.