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Suppose $x[n]$ is an absolutely summable discrete-time signal. Its $z$-transform is a rational function with two poles and two zeroes. The poles are at $z = \pm 2j.$ Which one of the following statements is TRUE for the signal $x[n]$?

1. It is a finite duration signal
2. It is a causal signal
3. It is a non-causal signal
4. It is a periodic signal.