Final answer:
The movement of a solute from a region of lower concentration to a region of higher concentration requires energy and is known as active transport, which depends on ATP.
Step-by-step explanation:
Among the options given, B. The movement of a solute from a region of lower concentration on one side of a membrane to a region of higher concentration on the other side requires an input of energy to occur. This process is known as active transport, and it occurs whenever a cell needs to move substances against their concentration gradient, which is from a lower concentration to a higher concentration. Energy is required because this movement is against the natural tendency of substances to move from areas of high concentration to areas of low concentration (passive transport).
Passive transport includes processes such as osmosis and simple diffusion, which do not require energy because molecules move down their concentration gradient. Conversely, active transport requires energy, often in the form of ATP (adenosine triphosphate), to move substances against their concentration gradient.