Why did conflict erupt between President Johnson and Congress after Lincoln’s assassination?

A Southern Congressmen agreed with President Johnson's Radical Reconstruction Plan.

B Republicans disagreed with President Johnson's Reconstruction Plan.
C Southern conservatives enacted the black codes against Congress’ wishes.
D Neither Congress nor the President wanted a Joint Committee on Reconstruction to dictate the plan.
The years immediately following the construction of the transcontinental railroad were years of astounding growth for the United States.

B Republicans disagreed with President Johnson's Reconstruction Plan.

President Johnson's Reconstruction Plan was seen as too lenient towards the Southern states and did not do enough to protect the rights of newly freed African Americans. Republicans in Congress wanted a more aggressive approach to Reconstruction, which led to conflict between President Johnson and the Republican-controlled Congress. This ultimately resulted in Johnson's impeachment in 1868.