The Haymarket Riot of 1886 is the answer you're looking for. The event was both responsible for the death of 4 anarchist rebels, as well as caused a steady decline of the Knights of Labor, due to the fears associated.
I believe the Long march took place in 1934 and 1935.
Its C I believe.
Hope it helps
What is what cause there is no meaning for it?.
A merchant uses resources found in his own country to make goods to sell in other countries.
