The degree of the differential equation $\;\Large c=\frac{\left[1+\left(\frac{dy}{dx}\right)^{3}\right]^{2/3}}{\frac{d^{3}y}{dx^{3}}}$ where $c$ is a constant

Question

$$\begin{array}{1 1}(1)1&(2)3\\(3)-2&(4)2\end{array}$$