Find the Composition $f ( x ) = x ^ { 2 } - 1$

Multiple Choice

Find the composition.
-If $f ( x ) = x ^ { 2 } - 1$ and $h ( x ) = \sqrt { x + 7 }$ , find $( h \circ f ) ( - 3 )$

A) $\sqrt { 9 }$
B) $\sqrt { 15 }$
C) $- 3 \sqrt { 6 }$
D) $2 + \sqrt { 7 }$