Machines were being used on farms around this time, so less people on farms were needed. So these people moved to cities for work.
Hope this helped :)
Its not A, America never had an alliance with NK.
Its not B. I took to test and B was wrong.
Its not C, the Gulf of Tonkin incident was during the war in Vietnam.
It has to be D.
Hope my suffering helped :)
The federalist party collapsed
It would be up to the states (citizens specifically)
The Huns, the Visigoths, and the Vandals