$\begin {array} {1 1} (A)\;36x^2+36y^2-36x-18y+11=0& \quad (B)\;36x^2+36y^2+36x-18y+11=0 \\ (C)\;36x^2+36y^2-36x-18y-11=0 & \quad (D)\;36x^2+36y^2+6x-18y-11=0 \end {array}$