This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Resting membrane potential is mainly due to 
Select and explain. 
A. Na+, B. K+, C. Cl-, D. Mg++
B: K+
Answer: B: K+ 
Explanation: Resting membrane potential depends on the concentration of potassium ion. (REF: TEXTBOOK OF MEDICAL PHYSIOLOGY GEETHA N 2 EDITION, 23)