For a cone, the equation for volume would be
V = π r^2 h/3.
( volume = pi x radius squared x height / 3)
To find the volume for this question, you would set up the equation like this:
V = π x 2^2 x 12 / 3
Then, following the order of operation, you would do the following:
V = π x 4 x 12 / 3
(You get the 4 from 2 squared)
V = π x 4 x 4
(You get the second 4 from dividing 12 by 3)
V = π x 16
(You get 16 from multiplying 4 and 4)
V = 16π
(You get 16π from multiplying 16 and π, and the number is always in front of the π, so you would never get a π16, it would only be 16π)
So, your volume would be 16π, which is answer D.
I hope I helped! c: