Final answer:
The Thirty Years' War fought between Protestants and Catholics in Central Europe, which lasted from 1618 to 1648, involved many European states and concluded with the Peace of Westphalia. so, option a is the correct answer.
Step-by-step explanation:
The conflict that was fought between Protestants and Catholics in Central Europe for over thirty years is known as the Thirty Years' War (1618 to 1648). This dispute engrossed much of Europe, with battles largely taking place in the terrain now known as Germany. The intensity of this conflict brought in various European powers such as Sweden, Denmark, the United Provinces of the Netherlands, and even France, which aligned with Protestant forces despite being a Catholic nation. This convergence was primarily due to political motivations, especially France's desire to achieve dominance in the region.
The Thirty Years' War led to significant devastation in the German lands through the incessant marches and skirmishes of mercenary armies, disrupting agriculture and displacing communities. However, the Protestant German states emerged victorious, which boosted France's position as the leading power in western Europe. The culminating Peace of Westphalia in 1648 recognized the sovereignty of the numerous entities forming the Holy Roman Empire, fundamentally altering the European political landscape.