Recall That the Average of a Function $f ( x )$

Recall that the average of a function $f ( x )$ on an interval $[ a , b ]$ is $\bar { f } = \frac { 1 } { b - a } \int _ { a } ^ { b } f ( x ) \mathrm { d } x$
Find the average of the given function.
$f ( x ) = \sin ( 5 x )$ over $[ 0,5 \pi ]$

A) Average = $\frac { 2 } { 25 \pi }$
B) Average = $\frac { 25 \pi } { 2 }$
C) Average = $\frac { \pi } { 5 }$
D) Average = $\frac { 25 \pi } { 4 }$
E) Average = $\frac { 5 } { \pi }$