What Was the Holy Alliance

What was the Holy Alliance?

A) a religious agreement between the pope and the Protestant countries of Europe
B) a religious agreement between Protestants,Catholics,and Eastern Orthodox leaders
C) the union of all European Christian kings against the Muslim Ottoman Turks
D) an international agreement between Russia,Prussia,and Austria pledging to act in accordance with the religious teachings of Christ
E) an agreement between European monarchs pledging to defend the Church from the attacks of the teachings of the French Revolution