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Reconstruction came to end when

Athe Fifteenth Amendment was ratified.
Bfederal troops were removed from the South.
CPresident Johnson was impeached.
Dthe Freedmen’s Bureau was dismantled.

Verified Answer :

Reconstruction came to end when "b. federal troops were removed from the South," since without the presence of federal troops the new laws under Reconstruction were almost impossible to enforce. 

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