Which document allowed for the United States to trade with other nations in China (free trade)?

the emancipation proclamation was the aim of the war change to include the freeing of slaves in addition to preserving the union. the 13th amendment, which abolished slavery in the u.s. was passed on december 6th 1865.

as promised, lincoln waited to unveil the proclamation until he could do so with success from the union military advance. on september 22nd 1862, after a victory at antietam, he publicly announced a preliminary emancipation proclamation, declaring all slaves free in the rebellious states as of january 1st 1863.

can someone me with this question:  

1) the end of the conflict between the north and the south didn’t just mark the end of a war; it marked the end of an entire way of life.” which statement best describes what this statement means?  

a) the southerners were no longer free and were controlled by the northern states.

b) the industrial economy in the north was not sustainable.

c) slavery became illegal, which changed completely the south’s labor force and the agricultural economy was destroyed.

d) the states decided to relinquish their independence and return to britain’s rule.