The correct answer is D) they believed the South should solve its own problems.
Many Northerners began to call for an end of Reconstruction because they believed the South should solve its own problems.
The Reconstruction program implemented by the government after the Civil War consisted of the restoration of the Union, the change of the society in the Southern states, and eliminating slavery. But as time went by, many radical Republicans considered that Reconstruction should end because the Southern states were the ones that must deal and solve with their own problems.