The radius of a right circular cylinder is increasing at a rate of 2 units per second. The height of the cylinder is decreasing at a rate of 5 units per second. Which of the following expressions gives the rate at which the volume of the cylinder is changing with respect to time in terms of the radius $r$ and height $h$ of the cylinder? (The volume $V$ of a cylinder with radius $r$ and height $h$ is $V = \pi r ^ { 2 } h$.) (A) $- 20 \pi r$ (B) $- 2 \pi r h$ (C) $4 \pi r h - 5 \pi r ^ { 2 }$ (D) $4 \pi r h + 5 \pi r ^ { 2 }$
The radius of a right circular cylinder is increasing at a rate of 2 units per second. The height of the cylinder is decreasing at a rate of 5 units per second. Which of the following expressions gives the rate at which the volume of the cylinder is changing with respect to time in terms of the radius $r$ and height $h$ of the cylinder?\\
(The volume $V$ of a cylinder with radius $r$ and height $h$ is $V = \pi r ^ { 2 } h$.)\\
(A) $- 20 \pi r$\\
(B) $- 2 \pi r h$\\
(C) $4 \pi r h - 5 \pi r ^ { 2 }$\\
(D) $4 \pi r h + 5 \pi r ^ { 2 }$