# Find the equation of the circle passing through $(0,0)$ and making intercepts a and b on the coordinate axes.
$\begin {array} {1 1} (A)\;x^2+y^2+ax+by=0 & \quad (B)\;x^2+y^2-ax+by=0 \\ (C)\;x^2+y^2+ax-by=0 & \quad (D)\;x^2+y^2-ax-by=0 \end {array}$