See attachment for one such shell. The volume is given by the sum of infinitely many thin shells like this, each with radius

and height determined by the vertical distance between the upper blue curve and the lower orange curve for any given

, i.e.

.
The volume is then
There’s no solution because x is less than 3 there is no way is greater than 5.
Hope this helps!
Definitely A because it is the only one that makes sense
Which of the models are the questions referring to?
8 because 24 divided by 3 is eight