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
The composition of which of the following is highest in the cell membrane? 
Select and explain. 
A. Proteins, B. Phospholipids, C. Cholesterol, D. Carbohydrates
A: Proteins
Answer: A: Proteins 
Explanation: As per the 12th Edition of Guyton, the following are the approximate composition of a cell membrane/ plasma membrane.

Proteins- 55%
Phospholipids- 25%
Cholesterol-13%
Other lipids- 4%
Carbohydrates- 3%