Why did congressional reconstruction end in 1877

With the compromise, the Republicans had quietly given up their fight for racial equality and blacks' rights in the south. In 1877, Hayes withdrew the last federal troops from the south, and the bayonet-backed Republican governments collapsed, thereby ending Reconstruction.

The Republican and Democratic parties effected a compromise agreement after the 1876 presidential election.

Explanation:

offline recommendation systems option b

because recommendation systems produce a list of two ways

1. through collaborative filtering

or

2. through content-based filtering