The Biggest Failure During the Reconstruction Period Was

The biggest failure during the Reconstruction period was:

A) not using legal and military means to stop the Ku Klux Klan in the South.
B) not allowing African-Americans to serve in the House of Representatives and Senate.
C) not providing an amendment to protect the right to vote for black men.
D) that African-Americans were not declared citizens.
E) that no help was given to African-Americans to achieve land ownership in the South.