Find the Largest Open Interval Where the Function Is Changing $\quad f ( x ) = \frac { 1 } { x ^ { 2 } + 1 }$

Multiple Choice

Find the largest open interval where the function is changing as requested.
-Increasing $\quad f ( x ) = \frac { 1 } { x ^ { 2 } + 1 }$

A) $( 1 , \infty )$
B) $( - \infty , 0 )$
C) $( - \infty , 1 )$
D) $( 0 , \infty )$