$\begin{array}{1 1} (A)\;y'y^2 + y^2 + 1 = 0 \\ (B)\;y'y - y^2 + 1 = 0 \\(C)\;y'y^2 - y^2 - 1 = 0 \\ (D)\;y'y^2 + y^2 - 1 = 0\end{array}$