What was the outcome of the Battle of Stalingrad

The last German troops in the Soviet city of Stalingrad surrender to the Red Army

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.