Correct answer: A. Martin Luther.
John Hus was an important predecessor of the Reformation, active in Bohemia (now a part of what we know as the Czech Republic). But the Roman Catholic Church was strong enough in his time, a century earlier than Luther, to stop Hus's work. Hus was condemned by the Council of Constance in 1415 and burned at the stake.
Rome was less able to stamp out a heretic when Martin Luther started his movement in Germany in 1517. The politics of the time had something to do with that. Luther's prince in Saxony, known as Frederick the Wise, protected Luther and kept him alive when his life was in danger. Luther was the most prominent of the reformers who launched the Protestant Reformation. Ulrich Zwingli in Switzerland and John Calvin, active in France and Switzerland, both contributed much to the Reformation as well. But Luther is generally given the credit as the one who began the Reformation.
