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
Characteristic feature true about outer membrane of peripheral nerve 
Select and explain. 
A. Relative permeable to sodium ions, B. Relative permeable to potassium ions, C. Permeable to chloride ions, D. Impermeable to potassium ions
B: Relative permeable to potassium ions
Answer: B: Relative permeable to potassium ions 
Explanation: None