The gravity model offers a logical explanation for the fact that

A) trade between Asia and the U.S. has grown faster than NAFTA trade.
B) trade in services has grown faster than trade in goods.
C) trade in manufactures has grown faster than in agricultural products.
D) Intra-European Union trade exceeds international trade by the European Union.
E) the U.S. trades more with Western Europe than it does with Canada.

D