Find the Length of the Curve $r = 3 \sin ^ { 3 } \left( \frac { \theta } { 3 } \right) , 0 \leq \theta \leq \frac { \pi } { 2 }$

Multiple Choice

Find the length of the curve.
-The curve $r = 3 \sin ^ { 3 } \left( \frac { \theta } { 3 } \right) , 0 \leq \theta \leq \frac { \pi } { 2 }$

A) $\frac { 9 } { 8 } ( 5 \pi - 8 )$
B) $\frac { 9 } { 64 } ( 5 \pi - 9 \sqrt { 3 } )$
C) $3 ( 3 \sqrt { 3 } - \pi )$
D) $\frac { 3 } { 8 } ( 2 \pi - 3 \sqrt { 3 } )$