How did regional issues test the nation's commitment to reconstruction?

the most difficult task confronting many Southerners during Reconstruction was devising a new system of labor to replace the shattered world of slavery. The economic lives of planters, former slaves, and nonslaveholding whites, were transformed after the Civil War.

Explanation:

the federalist party which advocated strong centralization dominated the united states government till 1800. so 1800 election transformed the power from one party to another party for the first time and was thus a turning point in american history. so jefferson called it "revolution of 1800".

explanation:

i think the answer is   b.