The probability density function 𝑓(𝑥) of a random variable 𝑋 which takes…

The standard normal-family density is f(x) = (1/(σ√(2π))) exp(-(x - μ)²/(2σ²)), for -∞ < x < ∞. The given density is (1/(3√(2π))) exp(-x²/18). Comparing terms gives μ = 0 and 2σ² = 18, so σ² = 9 and σ = 3. Therefore X follows a normal distribution. The correct option is Normal.