The Thirty Years' War That Devastated the Holy Roman Empire

The Thirty Years' War that devastated the Holy Roman Empire began when

A) the Bohemians chose a Protestant as their king.
B) the Swedish king Gustavus Augustus attacked the Empire.
C) Charles V retired to a monastery.
D) Jan Hus challenged the authority of the Catholic Church.
E) Savoy, the Palatine, and the United Provinces united against the House of Hapsburg.