Final answer:
Active transport moves solutes from a hypotonic (lower concentration) to a hypertonic (higher concentration) fluid, requiring ATP energy. The sodium-potassium pump exemplifies this process, utilizing protein pumps within the cell membrane.
Step-by-step explanation:
Active transport pumps typically move solutes from an area of lower concentration to one of higher concentration. This is against the solute's concentration gradient and requires energy in the form of ATP. The correct option for the movement of solutes is from hypotonic to hypertonic fluids, which means from a region with a lower solute concentration to a region with a higher solute concentration.
The sodium-potassium pump is an example of active transport, as it moves sodium ions out of the cell, where they are less concentrated, to the outside, where they are more concentrated. Similarly, it moves potassium ions into the cell against their concentration gradient. These movements, facilitated by transport proteins in the cell membrane that act like pumps, are crucial for maintaining the necessary concentration of ions inside and outside of the cell.