History question related to the post civil war

"the attempt to make black men american citizens was in a certain sense all a failure, but a splendid failure."—w. e.b. dubois (1868-1963), african american historian and activist

what does dubois mean by "a splendid failure"?

a. he saw radical reconstruction as a wondrous time for african american history, where anything seemed possible.
b. while efforts to gain civil rights for freedmen did not survive, they did have some enduring achievements such as public schools.
c. activists for civil rights learned many great lessons about how people would resist, undermine, and circumvent their work.
d. state laws that restricted the rights of freedmen also contained many provisions that went underappreciated.