Determine order and degree (if defined) of differential equation$\bigg(\large\frac{d^2y}{dx^2}\bigg)^2+\normalsize \cos\bigg(\large\frac{dy}{dx}\bigg)=0$

Question

$\begin{array}{1 1}order4, degree\;not\;defined \\order3, degree\;not\;defined \\ order1, degree\;not\;defined \\order2, degree\; not\; defined \end{array}$