Final answer:
The Thirty Years' War occurred from 1618 to 1648, which corresponds to answer A. This conflict primarily affected the Holy Roman Empire and was one of several significant European conflicts in the Late Middle Ages and Early Modern period.
Step-by-step explanation:
The Thirty Years' War ranged from 1618 to 1648, making option A) 1618-1648 the correct answer. This devastating conflict took place primarily within the territories of the Holy Roman Empire and was fought largely on religious grounds, with Protestant and Catholic states opposing each other. Alongside German Catholics, Lutherans, and Calvinists, other European nations such as Sweden, Denmark, and France also took part in the war. The resulting Peace of Westphalia not only brought an end to the conflict but also led to significant political changes including the recognition of state sovereignty within the fractured Holy Roman Empire.
Other significant European conflicts around this period were the Hundred Years' War (1337-1453) between England and France, and various civil wars and interstate conflicts throughout medieval Europe that contributed to the shaping of modern state boundaries and political powers.