Express the Area of the Region Bounded by the Given $y = e ^ { x }$

Multiple Choice

Express the area of the region bounded by the given line(s) and/or curve(s) as an iterated double integral.
-The curve $y = e ^ { x }$ and the lines $x + y = 3$ and $x = 3$

A) $\int _ { 0 } ^ { 3 } \int _ { 3 - x } ^ { e ^ { x } } d y d x$
B) $\int _ { 0 } ^ { 3 } \int _ { 3 } ^ { e ^ { x } - x } d y d x$
C) $\int _ { 0 } ^ { 3 } \int _ { \mathrm { x } } ^ { \mathrm { e } ^ { \mathrm { x } } - \mathrm { x } } \mathrm { dydx }$
D) $\int _ { 0 } ^ { 3 } \int _ { x - 3 } ^ { e ^ { x } } d y d x$