Evaluate: \(\int^{z}_{0}(sin x - cos x) dx \hspace{1mm}

Where\hspace{1mm}letter\hspace{1mm}z = \frac{\pi}{4}. (\pi = pi)\)

• A.\(\sqrt{2 +1}\)
• B.\(\sqrt{2 }-1\)
• C.\(-\sqrt{2 }-1\)
• D.\(1-\sqrt{2}\)
• E.