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 = ±2j. Which one of the following statements is TRUE for the signal x[n]?

• A. It is a finite duration signal.
• B. It is a causal signal.
• C. It is a non-causal signal.
• D. It is a periodic signal.