Find the Vertex of the Parabola by Completing the Square $y=x^{2}-3 x-9$

Multiple Choice

Find the vertex of the parabola by completing the square.
- $y=x^{2}-3 x-9$

A) $(1.5,-11.25)$
B) $(-1.5,-9.25)$
C) $(-1.5,-11.25)$
D) $(1.5,6.75)$