Find All Solutions of the Equation $$x ^ { 4 } + 16 = 0$$

Multiple Choice

Find all solutions of the equation. Leave answers in trigonometric form.
- $$x ^ { 4 } + 16 = 0$$

A) $\left\{ 2 \operatorname { cis } 45 ^ { \circ } , 2 \operatorname { cis } 315 ^ { \circ } , 2 \right.$ cis $135 ^ { \circ } , 2$ cis $\left. 225 ^ { \circ } \right\}$
B) $\left\{ \sqrt { 3 } \operatorname { cis } 26.565 ^ { \circ } , \sqrt { 3 } \operatorname { cis } 333.435 ^ { \circ } , \sqrt { 3 } \operatorname { cis } 153.435 ^ { \circ } , \sqrt { 3 } \operatorname { cis } 206.565 ^ { \circ } \right\}$
C) $\left\{ 16 \operatorname { cis } 45 ^ { \circ } , 16 \operatorname { cis } 315 ^ { \circ } , 16 \right.$ cis $135 ^ { \circ } , 16$ cis $\left. 225 ^ { \circ } \right\}$
D) $\left\{ \sqrt { 2 } \operatorname { cis } 45 ^ { \circ } , \sqrt { 2 } \operatorname { cis } 315 ^ { \circ } , \sqrt { 2 } \operatorname { cis } 135 ^ { \circ } , \sqrt { 2 } \operatorname { cis } 225 ^ { \circ } \right\}$