Write the given trigonometric function in terms of $\cos x$.
$\csc x$

$\pm \frac{\sqrt{1-{\cos }^{2}x}}{1+{\cos }^{2}x}$

$\pm \frac{\sqrt{1-{\cos }^{2}x}}{1-{\cos }^{2}x}$

$\pm \frac{\sqrt{1+{\cos }^{2}x}}{1-{\cos }^{2}x}$

$\pm \frac{\sqrt{1+{\cos }^{2}x}}{1+co{s}^{2}x}$