Random variables and random processes. A. Write the probability density function (PDF) of a Gaussian random variable (x) with mean of (μ) and variance of (σ²).

a) (f(x) = 1/√2πσ² e-(x-μ)²/2σ²)
b) (f(x) = 1/σ√2π e-(x-μ)²/2σ²)
c) (f(x) = 1/√πσ e-(x-μ)²/2σ)
d) (f(x) = 1/√2πσ e-(x-μ)²/σ)