Given circle (c),
$x^2+y^2+4 x-4 y+4=0$
On comparing with its general form
$x^2+y^2+2 g x+2 f y+c=0$
whose center $=(-g,-f)$ and radius $=\sqrt{g^2+f^2-c}$
$\Rightarrow \quad g=2, f=-2, c=4$
$\therefore$ Center $=(-2,2)$ and radius $=\sqrt{4+4-4}=2$
With the help of diagram, we can see that it touches $X$-axis and
$Y$-axis.
