Find the Derivative of the Function $f ( \theta ) = \frac { 3 } { 7 } \sin ^ { 2 } 3 \theta$

Multiple Choice

Find the derivative of the function. $f ( \theta ) = \frac { 3 } { 7 } \sin ^ { 2 } 3 \theta$

A) $f ^ { \prime } ( \theta ) = \frac { 3 \sin 3 \theta \cos 3 \theta } { 7 }$
B) $f ^ { \prime } ( \theta ) = \frac { 18 \sin 3 \theta \cos 3 \theta } { 7 }$
C) $f ^ { \prime } ( \theta ) = \frac { 18 \cos 3 \theta } { 7 }$
D) $f ^ { \prime } ( \theta ) = - \frac { 18 \sin 3 \theta \cos 3 \theta } { 7 }$
E) $f ^ { \prime } ( \theta ) = \frac { 18 \sin 3 \theta } { 7 }$