2:5
4:10
8:20
16:40
Hope that helps:)
I think your answer is c but I'm not sure
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
(5^-2 ● 4^-4)^-2
you need to multiply tge power of tge outside the bracket with tge power inside the bracket to eliminate the power
= 5^4 ● 4^8
the answer is A