Simplify the Expression Algebraically $$\frac { 9 } { \sqrt { 2 } } \cos \left( \frac { 5 \pi } { 4 } - x \right)$$

Multiple Choice

Simplify the expression algebraically.​ $$\frac { 9 } { \sqrt { 2 } } \cos \left( \frac { 5 \pi } { 4 } - x \right)$$ ​

A) - $\frac { 9 } { 2 }$ $( \cos x + \sin x )$
B) $\frac { 9 } { 2 }$ $( \cos x - \sin x )$
C) $\frac { 9 } { 2 }$ $\left( \cos \frac { 5 x } { 4 } + \sin \frac { 5 x } { 4 } \right)$
D) $\frac { 9 } { 2 }$ $( \sin x - \cos x )$
E) $\frac { 9 } { 2 }$ $\left( \cos \frac { 5 x } { 4 } - \sin \frac { 5 x } { 4 } \right)$