Express the Area of the Region Bounded by the Given $\int _ { 0 } ^ { 3 } \int _ { 0 } ^ { y / 7 } \mathrm { dx } \mathrm { dy }$

Multiple Choice

Express the area of the region bounded by the given line(s) and/or curve(s) as an iterated double integral.
-The lines x = 0, y = 3x, and y = 7

A) $\int _ { 0 } ^ { 3 } \int _ { 0 } ^ { y / 7 } \mathrm { dx } \mathrm { dy }$
B) $\int _ { 0 } ^ { 3 } \int _ { 0 } ^ { x / 7 } \mathrm { dydx }$
C) $\int _ { 0 } ^ { 7 } \int _ { 0 } ^ { y / 3 } \mathrm { dx } \mathrm { dy }$
D) $\int _ { 0 } ^ { 7 } \int _ { 0 } ^ { y / 3 } \mathrm { dydx }$