Trigonometric Range Evaluation

$E(x) = 0.5 + \cos x^\circ - \sin x^\circ = 0.5 + \sqrt{2}\cos(x + 45^\circ).$ For $x = 15^\circ$, $\cos 15^\circ - \sin 15^\circ \approx 0.9659 - 0.2588 = 0.7071$. $E(15^\circ) = 0.5 + 0.7071 = 1.2071$. For $x = 5^\circ$, $\cos 5^\circ - \sin 5^\circ \approx 0.9962 - 0.0872 = 0.9090$. $E(5^\circ) = 0.5 + 0.9090 = 1.4090$. So the expression takes values in $[1.2071, 1.4090]$, which are all $> 1$. None of options A-D capture this range.