Use the First Derivative Test to Determine the Location of Each

Multiple Choice

Use the first derivative test to determine the location of each local extremum and the value of the function at thatextremum.
- $f(x) =3 x e^{-x}$

A) No local extrema
B) Local minimum at $\left(1, \frac{3}{\mathrm{e}}\right)$
C) Local maximum at $\left(1, \frac{3}{\mathrm{e}}\right)$
D) Local minimum at $\left(3, \frac{3}{\mathrm{e}}\right) ^{\text {) }}$