The length of a swimming pool is 22 ft. The width is 40 ft. If the volume of the pool is 2,500 ft³, which equation below could be used to find the depth of the pool?

A.(22 + 40)x = 2500
B.22 + 40 + x = 2500
C.66x = 2500
D.22 • 40 • x = 2500