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: ENT
Fluid, which has high potassium and low sodium contents, is - 
Select and explain. 
A. CSF, B. Ectolymph, C. Endolymph, D. Pleural fluid
C: Endolymph
Answer: C: Endolymph 
Explanation: None