Use the Graph to Find the Intervals on Which It $( - \infty , \infty )$

Use the graph to find the intervals on which it is increasing, decreasing, or constant.
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A) Increasing on $( - \infty , \infty )$
B) Increasing on $\left( - \pi , - \frac { \pi } { 2 } \right)$ and $\left( \frac { \pi } { 2 } , \pi \right)$ ; decreasing on $\left( - \frac { \pi } { 2 } , \frac { \pi } { 2 } \right)$
C) Decreasing on $\left( - \pi , - \frac { \pi } { 2 } \right)$ and $\left( \frac { \pi } { 2 } , \pi \right)$ ; increasing on $\left( - \frac { \pi } { 2 } , \frac { \pi } { 2 } \right)$
D) Decreasing on $( - \pi , 0 )$ ; increasing on $( 0 , \pi )$