Use a Graphing Dervice to Draw the Graph of the Function

Use a graphing dervice to draw the graph of the function $f ( x ) = - 3 - 3 x ^ { 2 }$ . State approximately the interval $s$ ) on which the function is increasing and on which the function is decreasing.

A) $f$ is increasing on $( - \infty , 0 ]$ and decreasing on $[ 0 , \infty )$
B) $f$ is increasing on $( - \infty , - 3 )$ and decreasing on $[ 3 , \infty )$
C) $f$ is increasing on $( - \infty , \infty )$
D) $f$ is decreasing on $[ 0 , \infty )$ only
E) none of these