$\sqrt {\large\frac{y}{x}}+\sqrt {\large\frac{x}{y}}$$=2=>\large\frac{dy}{dx}=$

Question

\[(a)\;\frac{x^2+y^2}{x+y}\quad (b)\;\frac{x^2-y^2}{x+y} \quad (c)\;1 \quad (d)\;2 \]