$\frac{d^2x}{dy^2}$ equals

Question

( A ) $-(\frac{d^2y}{dx^2}) (\frac{dy}{dx})^{-3}$
( B ) $(\frac{d^2y}{dx^2}) (\frac{dy}{dx})^{-3}$
( C ) $(\frac{d^2y}{dx^2})^{-1}$
( D ) $-(\frac{d^2y}{dx^2})^{-1} (\frac{dy}{dx})^{-3}$