The Federal Courts Took the Lead in Combating Segregation but Faced

The federal courts took the lead in combating segregation but faced a number of hurdles in implementing their decisions until Congress passed the 1964 Civil Rights Act.Which institution of the American political system best explains the difficulty the courts had in enforcing their rulings on desegregation?

A) equal protection clause
B) judicial review
C) privileges and immunities clause
D) federalism
E) separation of powers