Let

$y=ta{n}^{-1}(u-1).$

Which $of$ the following $is$ the derivative $ofy?$

$\frac{dy}{du}=\frac{1}{1+(u-1{)}^2}$

$\frac{dy}{du}=\frac{-1}{1+(u-1{)}^2}$

$\frac{dy}{du}=-cs{c}^2(u-1)$

$\frac{dy}{du}=\frac{1}{\sqrt[\phantom{2}]{1+(u-1{)}^2}}$

None $of$ the above.