The sodium-potassium pump is an example of: (A) Active transport, (B) Passive transport, (C) Facilitated diffusion, (D) Osmosis
Answer is A. In Na+– K+ exchange, 3Na+ goes out and 2K+ goes into the cell with the utilization of ATP. 
Hence it is a primary active transport. Due to the net flow of Na+ outwards, there is a potential difference that occurs.