Find the X-Intercepts (If Any) for the Graph of the Quadratic

Multiple Choice

Find the x-intercepts (if any) for the graph of the quadratic function.
- $f ( x ) = x ^ { 2 } + 12 x + 15$ Give your answers in exact form.

A) $( - 6 \pm \sqrt { 21 } , 0 )$
B) $( 6 + \sqrt { 21 } , 0 )$
C) $( 6 \pm \sqrt { 15 } , 0 )$
D) $( - 12 \pm \sqrt { 15 } , 0 )$