Find the Given Power $\left[ 2 \operatorname { cis } 15 ^ { \circ } \right] ^ { 4 }$

Multiple Choice

Find the given power. Write answer in rectangular form.
- $\left[ 2 \operatorname { cis } 15 ^ { \circ } \right] ^ { 4 }$

A) $8 + 8 i \sqrt { 3 }$
B) $16 \mathrm { i }$
C) $8 + 8 \mathrm { i }$
D) $8 \sqrt { 3 } + 8 i$