The correct answer is option 3, Metternich. The Congress of Vienna was convened in 1815 to discuss the aftermath of the Napoleonic Wars and the reorganization of Europe. Metternich, who was the Foreign Minister of Austria at the time, played a crucial role in organizing and leading the Congress. He was known for his conservative and reactionary policies, and his main goal was to restore a balance of power in Europe and to prevent future revolutionary movements. Metternich, along with other European leaders and diplomats, negotiated and agreed upon a series of treaties and agreements that aimed to maintain stability and peace in Europe for the next several decades. This included the redrawing of national boundaries and the establishment of a system of international cooperation and diplomacy.