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

1. The region inside the circle of radius $0.5$ and centered at origin
2. The region outside the circle of radius $0.25$ and centered at origin
3. The annular region between the two circles, both centered at origin and having radii $0.25$ and $0.5$
4. The entire $Z$ plane.

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