Final answer:
When Pope Leo X threatened to excommunicate Martin Luther, Luther's reaction was option C: He burned the Papal Bull as a sign of rebellion. This act marked a turning point in the Protestant Reformation.
Step-by-step explanation:
When Pope Leo X threatened to excommunicate Martin Luther, Luther's reaction was option C: He burned the Papal Bull as a sign of rebellion. This event took place in 1520 when Luther publicly burned a copy of the Papal Bull, which was a document issued by the Pope condemning Luther's ideas and giving him 60 days to recant.
Luther's act of burning the Papal Bull was seen as a symbol of his defiance against the authority of the Pope and the Catholic Church. It marked a turning point in the Protestant Reformation, as Luther's actions further fueled the spread of his ideas and attracted more followers.
By choosing to burn the Papal Bull, Luther made it clear that he was not willing to recant his ideas and submit to the authority of the Pope. This act demonstrated Luther's firm belief in his own teachings and set the stage for the formation of a separate Protestant movement.
Learn more about Martin Luther's reaction to Pope Leo X's threat