The Diagram Below Shows the (Hypothetical)demand and Supply Curves for Regional

The diagram below shows the (hypothetical) demand and supply curves for regional jets in Canada.Assume that the market is competitive,all jets are identical,and that Canada engages in international trade.
FIGURE 33- 6
-Since 1950,the world's real GDP has increased by seven times and the volume of world trade has increased by roughly

A) the same amount.
B) thirty times.
C) two times.
D) fifteen times.
E) ten times.