Hey!
So ..
A is out because the declaration of independence doesn't talk about getting territories , it just talks about how the U.S gained Independence at long last from Britain
B is out because the Articles of Confederation basically was an early "failed" constitution that could not place taxes.
C is out . bill of rights is just a list of rights that we as people have and how these rights are protected and can not be taken away from us.
D is your answer...
The Northwest Ordinance was a document that was passed July 13, 1787 which established a process for new states to be gained and they can become part of the U.S territory.
Hope this helped :)
~Queen Hanaenae