Let $f ( x ) = \sqrt { x + 1 } , g ( x ) = x ^ { 2 } - 1$

Multiple Choice

Let $f ( x ) = \sqrt { x + 1 } , g ( x ) = x ^ { 2 } - 1$ . Find the domain of the composite function. $( f \circ g ) ( x )$

A) $\quad ( - 1 , \infty )$
B) $\quad ( - \infty , - 1 ]$
C) $\quad ( - \infty , - 1 )$
D) $[ - 1 , \infty )$
E) $\quad ( - \infty , \infty )$