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
Sodium-potassium pump is a type of ? 
Select and explain. 
A. Passive transpo, B. Primary active transpo, C. Secondary active transpo, D. Counter transpo
B: Primary active transpo
Answer: B: Primary active transpo 
Explanation: Ans. is 'b' i.e., Primary active transpo