The Largest Set on Which the Function $f ( x ) = x e ^ { x }$

Multiple Choice

The largest set on which the function $f ( x ) = x e ^ { x }$ is increasing is

A) $( - \infty , \infty )$
B) $( - \infty , \infty )$ .
C) $( 0 , \infty )$
D) $( - \infty , 1 )$
E) $( - 1 , \infty )$