Consider a discrete time signal given by
$x[n]= (-0.25)^{n} u[n]+(0.5)^{n} u [-n-1]$
The region of convergence of its $Z$-transform would be
- The region inside the circle of radius $0.5$ and centered at origin
- The region outside the circle of radius $0.25$ and centered at origin
- The annular region between the two circles, both centered at origin and having radii $0.25$ and $0.5$
- The entire $Z$ plane.