Find the Axis of Symmetry of the Parabola Defined by the Given

Multiple Choice

Find the axis of symmetry of the parabola defined by the given quadratic function.
- $$f ( x ) = x ^ { 2 } + 7$$

A) $x = 0$
B) $x = 7$
C) $x = - 7$
D) $y = 7$ y