A Balloon (In the Shape of a Sphere) Is Being $\left( \mathrm { V } { } ^ { \circ } \mathrm { r } \right) ( \mathrm { t } )$

Multiple Choice

A balloon (in the shape of a sphere) is being inflated. The radius is increasing at a rate of 4 cm per second. Find a function, r(t) , for the radius in terms of t . Find a function, V(r) , for the volume of the balloon in terms of r . Find $\left( \mathrm { V } { } ^ { \circ } \mathrm { r } \right) ( \mathrm { t } )$

A) $( \mathrm { V } \cdot \mathrm { r } ) ( \mathrm { t } ) = \frac { 320 \pi \mathrm { t } ^ { 2 } } { 3 }$
B) $\left( V { } ^ { \circ } r \right) ( t ) = \frac { 112 \pi t ^ { 3 } } { 3 }$
C) $( \mathrm { V } \circ \mathrm { r } ) ( \mathrm { t } ) = \frac { 256 \pi t ^ { 3 } } { 3 }$
D) $( \mathrm { V } \circ \mathrm { r } ) ( \mathrm { t } ) = \frac { 1024 \pi \sqrt { \mathrm { t } } } { 3 }$