Solve the Equation by Using the Square Root Property $$x ^ { 2 } + 9 = 0$$

Multiple Choice

Solve the equation by using the square root property. Express any complex numbers using i notation.
- $$x ^ { 2 } + 9 = 0$$

A) $x = - 4.5$
B) $x = 3 i$
C) $x = \pm 3 \mathrm { i }$
D) $x = \pm 4 \mathrm { i }$