Find the Formula for the Function $V = \frac { 4 } { 3 } \pi r ^ { 3 }$

Multiple Choice

Find the formula for the function.
-Express the volume of a sphere as a function of its radius r.

A) $V = \frac { 4 } { 3 } \pi r ^ { 3 }$
B) $V = \frac { 3 } { 4 } \pi r ^ { 3 }$
C) $V = \pi r ^ { 3 }$
D) $V = \frac { 2 } { 3 } \pi r ^ { 2 }$