# Find the equation of the circle with centre (1,1) and radius $\sqrt 2$
$\begin {array} {1 1} (A)\;x^2+y^2+2x+2y=0 & \quad (B)\;x^2+y^2-2x-2y=0 \\ (C)\;x^2+y^2-2x+2y=0 & \quad (D)\;x^2+y^2+2x-2y=0 \end {array}$