Consider a low pass random process with a white noise power spectral density
$$ S_{x} (\omega)=\frac{N}{2}$$ where $$-2 \pi B \leq \omega \leq 2 \pi B $$
                    0 elsewhere
The Auto-correlation function $$R_{x}(\tau)$$ is

A

$$2NBsinc(2\pi B \tau)$$

B

$$\pi NBsinc(2\pi B \tau)$$

C

$$ NBsinc(2\pi B \tau)$$

D

none of the above