Question

Consider a basic cylindrical vase. An example is shown. We
will let V denote the volume of water in the vase (in cubic
inches) and d denote the depth of water in the vase (in inches)
and we will consider V to be a function of d.
a. Plot the graph of V versus d where V appears on the
vertical axis.
b. Give a thorough explanation using complete sentences
of why your plot is appropriate.

I got part A but i don't know how i would explain it in part B.
please help(: