Answer:
According to the diagram, ATP is most likely being used for substance A to enter the cell.
Step-by-step explanation:
ATP is necessary for the transport of substances against their concentration gradient, participating in the active transmembrane transport.
In the diagram (see picture) substance A has a higher intracellular concentration, and a lower one in the extracellular space. For this substance to enter the cell it is necessary to use an active transport that requires ATP, in order to pass against its gradient.
With respect to the other options:
- Substance B probably does not require ATP because it can enter by diffusion following its concentration gradient.
- Both substances enter the cell, but only A requires the use of ATP in its transport.