Why Did Boeing Use a Different Model for Designing and Manufacturing

Why did Boeing use a different model for designing and manufacturing the 787 Dreamliner than it used for the 747?

A) because lawmakers in Washington, D.C., urged Boeing to provide a firm economic foundation for American workers in Washington state
B) because NAFTA regulations prevented using the same model for the 787 that was used for the 747
C) because the 787 Dreamliner would be made entirely of aluminum, necessitating an entirely new fabrication procedure
D) because the 747 was the worst commercial aviation failure since the Spruce Goose and Boeing had to try something different in order to be profitable
E) because the structural foundations of American society had become much more global since the 747 was built