Moderate# Volume by Washers

APCALC-BXQOKF

Let $R$ be the region in the first quadrant bounded by the graphs of $y=e^{x}$, $x=1$ and the $x$ and $y$ axes. If $R$ is revolved about the horizontal line $y$ = $e$, the volume of the resulting solid is represented by which of the following integral expressions?