Who initiated the spark of opposition to the Catholic Church in November 1517, leading to the movement known as the Reformation?

Explanation

Martin Luther is credited with starting the Reformation by posting his Ninety-Five Theses in November 1517, challenging the Catholic Church's practices and doctrines. While figures like Henry VIII and John Calvin played significant roles in religious changes later, it was Luther who first ignited the movement. Pope Clement VII was a later pope and not responsible for initiating the Reformation.