What is Discrete Time Fourier Transform (DTFT) of following signal?
$$x(n) = a^n$$ where $$n \geq 0, -1 < a < 1$$

A

$$X(\omega) = \frac{1}{(1 - ae^{-j \omega})}$$

B

$$X(\omega) = \frac{1}{(1 + ae^{-j \omega})}$$

C

$$X(\omega) = \frac{a}{(1 - ae^{-j \omega})}$$

D

$$X(\omega) = \frac{a}{(1 + ae^{-j \omega})}$$