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
Serpentine receptor is a: 
Select and explain. 
A. Three pass transmembrane protein, B. Five pass transmembrane protein, C. Seven pass transmembrane protein, D. Nine pass transmembrane protein
C: Seven pass transmembrane protein
Answer: C: Seven pass transmembrane protein 
Explanation: Serpentine Receptors are G protein coupled receptors that span the cell membrane seven times (seven pass transmembrane protein). Ref: Ganong's Review of Medical Physiology, 21st Edition, Page 42