A spherical balloon is filled with $4500 \pi$ cubic meters of helium gas. If a leak in the balloon causes the gas to escape at the rate if $72 \pi$ cubic meters per minute, then the rate (in meters per minute) at which the radius of the ballon decreases 49 minutes after the leakage began is

Question

( A ) $\frac{2}{9}$
( B ) $\frac{7}{9}$
( C ) $\frac{9}{7}$
( D ) $\frac{9}{2}$