The correct answer is B.
The Compromise of 1877 has an informal agreement reached during the due to the intense competition in the presidential elections in 1976. The agreement decided to remove federal troops from the Southern States and this was the formal ending of the Reconstruction era. Moreover, the Republican Hayes was appointed President instead of the Democrat Tilden. All these provisions were part of the deal.
On the other hand, Jim Crow Laws were contemporary to the other options listed, and also a consequence of the situation during and at the end of the Reconstruction era, but they were not directly implemented by the Compromise of 1877. The Jim Crow laws were used to enforce segregation in terms of race in the Southern states, circumventing the non-discrimination provisions of the 14th and 15th amendments of the US Constitution.
The Umayyads were unable to conquer the nascent Christian Kingdoms in the North which included but were not limited to: Leon, Castille, the Basque Territories, and the Catalonian Counties. In addition, the Umayyads were not able to prevent the fragmentation of their territory into the Taifa Kingdoms in 1038.
Your answer is right!
"Whenever we ice skate, we put on our mittens." is a noun clause.
