The correct answer to this question is C, Pi x r2 x h. Pi, in this question, corresponds with the number 3.142. R stands for radius, which would be the radius of the cylinder. This radius is from the end of the cylinder. Lastly, h stands for height, which is the height of the cylinder.

To properly calculate the volume, the height and radius must be the same units of measurement. If they are not, they need to be converted to match. The volume that is found from using the formula Pi x r2 x h is in the measurement of cubic units.