Strange as it may seem, NONE of the choices on the list
is the volume of that cylinder,
The volume of any cylinder is (π) (radius)² (height).
We know all of these numbers. We only need to pour them into
the hopper on top of the volume machine, and turn the crank.
(π) x (radius)² x (height)
= (3.14...) x (7 units)² x (8 units)
= (3.14...) x (49 units² x 8 units)
= (3.14...) x (392 units³) = 1,231.5... units³
I don't see that number among the choices, or anything close to it.
Choice-D is interesting. As we saw during our calculation,
392 is (radius)² x (height). But that's not the volume, because
it hasn't been multiplied by π yet.