# Which of following satisfy the differential equation $y'+2xy=0?$
$(a)\;y=ce^{-x^2}, y'+2xy=0 \\ (b)\;y=x \log x-x,y'= \log x^2 \\ (c)\;y=\sin ^{-1}x, y''= \frac{x^2}{(1-x^2)^{3/2}}\\ (d)\;y=A e^{-1/x}, x^2y'-x-y=0$