Why must integration be used to find the work required to pump water out of a tank?

A. Different volumes of water are moved different distances.

B. Water from the same horizontal planes is lifted different distances.

C. Integration is necessary because the acceleration of gravity changes at each level.

D. Integration is necessary because W = mgy.

A. Different volumes of water are moved different distances.

Step-by-step explanation:

Integration is used to find work required to pump water out of a tank because different volumes of water are moved different distances and to sum it all we the tool required is integration. Moreover, work done is a path function or an inexact differential. It does depend upon the path followed by the process.

hence the correct answer is A.