As de jure segregation formed and solidified in the south:
(a)-levels of residential separation between the races decreased.
(b)-levels of prejudice and racism increased.
(c)-lynching virtually ceased
(d)-african americans began moving from the north back to the south.
(d)levels of educational and economic opportunity increased for african americans

(b)-Levels of prejudice and racism increased.

Explanation:

In the South, there was the Jim Crow Laws. This legislation was related to the segregation of citizens in the cities of the South, giving a considerable highlight to the white people. The origin of these laws, namely the Black Codes, can be traced after the sign of the 13th Amendment (the Abolition of Slavery) in 1865. Black Codes strictly determined where black people could work, live or walk, and these codes would strenght through the years, especially after the rising of the Ku Klux Klan.

The answer is b

Explanation:

The levels of prejudice and racism increased as a consequence of the Jim Crow laws, passed in 1865. These laws were passed in order to regulate all aspects of people's lives, including their jobs, education, compensation, entertainment, amongst others. The idea was to separate the regular activities of African Americans from those of white people, contributing to allowing for more prejudice and racism.  Black people were even attacked by the law, making it difficult for them to live as free men.