Which Equation Shown Is Correct for a Normal Distribution with a Mean

Multiple Choice

Which equation shown is correct for a normal distribution with a mean of 20 and a variance of 10?

A) $f(x) =\frac{1}{\sqrt{20 \pi}} e^{\frac{-(x-10) ^{2}}{200}}$
B) $f(x) =\frac{1}{\sqrt{20 \pi}} e^{\frac{-(x-20) ^{2}}{200}}$
C) $f(x) =\frac{1}{\sqrt{200 \pi}} e^{\frac{-(x-10) ^{2}}{32}}$
D) $f(x) =\frac{1}{\sqrt{200} \pi} e^{\frac{-(x-20) ^{2}}{32}}$