For the function $f(x)=\frac{e^{-\lambda}}{\sigma \sqrt{2 \pi}},$ where $\lambda=\frac{1}{2 \sigma^{2}}(x-\mu)^{2},$ and $\sigma$ and $\mu$ are
constants, the maximum occurs at
(A) $x=\sigma$
(B) $\quad x=\sigma \sqrt{2 \pi}$
(C) $x=2 \sigma^{2}$
(D) $x=\mu$
For the function $f(x)=\frac{e^{-\lambda}}{\sigma \sqrt{2 \pi}},$ where $\lambda=\frac{1}{2 \sigma^{2}}(x-\mu)^{2},$ and $\sigma$ and $\mu$ are
constants, the maximum occurs at
(A) $x=\sigma$
(B) $\quad x=\sigma \sqrt{2 \pi}$
(C) $x=2 \sigma^{2}$
(D) $x=\mu$