Solve the Problem $8 \mathrm { in } / \mathrm { sec }$

Multiple Choice

Solve the problem. Round your answer, if appropriate.
-The radius of a right circular cylinder is increasing at the rate of $8 \mathrm { in } / \mathrm { sec }$ , while the height is decreasing at the rate of 9 in./sec. At what rate is the volume of the cylinder changing when the radius is 7 in. and the height is 20 in.?

A) $- 257$ in. $3 / \mathrm { sec }$
B) $679 \pi$ in. $3 / \mathrm { sec }$
C) 679 in. $_ { 3 } ^ { 3 } / \mathrm { sec }$
D) $1799 \pi$ in. $3 / \mathrm { sec }$