During the First Half of the Fifteenth Century, the Conciliar

During the first half of the fifteenth century, the conciliar movement in the Catholic Church:

A) tried to reunite the Roman Catholic and Orthodox churches.
B) unsuccessfully attempted to conciliate the protestants of Germany and Bohemia.
C) succeeded, after a long struggle, in reducing the pope's authority to that of a constitutional monarch and ended the practices of simony and nepotism.
D) reunited Roman Catholicism, extirpated heresy, and sought to reform the church from top to bottom.