Perform the Operation Shown Below and Leave the Result in Trigonometric

Multiple Choice

Perform the operation shown below and leave the result in trigonometric form. $\left[ 4 \left( \cos \frac { 2 \pi } { 3 } + i \sin \frac { 2 \pi } { 3 } \right) \right] \left[ 3 \left( \cos \frac { 3 \pi } { 7 } + i \sin \frac { 3 \pi } { 7 } \right) \right]$

A) $7 \left( \cos \frac { 23 \pi } { 21 } + i \sin \frac { 23 \pi } { 21 } \right)$
B) $12 \left( \cos \frac { 23 \pi } { 21 } + i \sin \frac { 23 \pi } { 21 } \right)$
C) $12 \left( \cos \frac { 2 \pi } { 3 } + i \sin \frac { 2 \pi } { 3 } \right)$
D) $12 \left( \cos \frac { 2 \pi } { 7 } + i \sin \frac { 2 \pi } { 7 } \right)$
E) $7 \left( \cos \frac { 2 \pi } { 7 } + i \sin \frac { 2 \pi } { 7 } \right)$