Find All Solutions of the Equation $$x ^ { 2 } - i = 0$$

Find all solutions of the equation. Leave answers in trigonometric form.
- $$x ^ { 2 } - i = 0$$

A) $\left\{ \operatorname { cis } 270 ^ { \circ } , \operatorname { cis } 90 ^ { \circ } \right\}$
B) $\left\{ \operatorname { cis } 45 ^ { \circ } , \operatorname { cis } 225 ^ { \circ } \right\}$
C) $\left\{ \operatorname { cis } 180 ^ { \circ } , \operatorname { cis } 0 ^ { \circ } \right\}$
D) $\left\{ \operatorname { cis } 315 ^ { \circ } , \operatorname { cis } 135 ^ { \circ } \right\}$