A spherical snowball is melting in such a manner that its radius is changing at a constant rate, decreasing from 36 cm to 9 cm in 30 minutes. At what rate, in cubic cm per minute, is the volume of the snowball changing at the instant the radius is 5 cm?
a) 675Ο
b) β90Ο
c) β80Ο
d) β180Ο
e) 45Ο
