The point of contact the circles $x^2+y^2+2x+2y+1=0$ and $x^2+y^2-2x+2y+1=0$ is

Question

$$\begin {array} {1 1} (a)\;(0,1) & \quad (b)\;(0,-1) \\ (c)\;(1,0) & \quad (d)\;(-1,0) \end {array}$$