The Z-transform of e-at is:

• A. \(\frac{z}{{z - {e^{ - a}}}}\)
• B. \(\frac{z}{{z + {e^{ - aT}}}}\)
• C. \(\frac{z}{{z - {e^{ - aT}}}}\)
• D. \(\frac{z}{{z - {e^{aT}}}}\)