Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
Solve the problem.
-The volume of a right cylindrical cone of height $6 \mathrm {~cm}$ and radius $\mathrm { r } \mathrm { cm }$ is $\mathrm { V } ( \mathrm { r } ) = 2 \pi \mathrm { r } ^ { 2 } \mathrm { cubic }$ centimeters (cm) . Find the instantaneous rate of change of the volume with respect to the radius $\mathrm { r } w h e n \mathrm { r } = 4 \mathrm {~cm}$ .

A) $16 \pi \mathrm { cm } ^ { 3 } / \mathrm { cm }$
B) $16 \mathrm {~cm} ^ { 3 } / \mathrm { cm }$
C) $4 \pi \mathrm { cm } ^ { 3 } / \mathrm { cm }$
D) $32 \pi \mathrm { cm } ^ { 3 } / \mathrm { cm }$