Answer:
it is b.
Explanation:
because of THE 4TH OF JULY...
All of the choices given were invented before 1840 except for the zipper. The zipper was invented in 189. The correct answer is B.
A lot of people died and wounded
Four U.S presidents have been assassinated, Abraham Lincoln, James Garfield, William McKinley, And John F. Kennedy(J.F.K).