Which of the following method is used to find the inverse z-transform of a signal?a.All of the optionsb.Counter integrationc.Expansion into a series of termsd.Partial fraction expansion

The method used to find the inverse z-transform of a signal is d. Partial fraction expansion.

Here's a step-by-step explanation:

1. Express the Z-transform in terms of its poles and zeros. This is typically given in a problem.

2. Decompose the Z-transform into simpler fractions using partial fraction expansion. This involves expressing the Z-transform as a sum of simpler fractions.

3. Look up each simpler fraction in the Z-transform table to find its time-domain counterpart. The Z-transform table is a list of common Z-transform pairs.

4. The inverse Z-transform of the signal is the sum of the time-domain counterparts found in step 3.

So, the correct answer is d. Partial fraction expansion.