Final answer:
Option A is correct; the Roman Catholic Church responded to Protestantism by convening the Council of Trent, which aimed to internally reform the Church and reaffirm its core doctrines as part of the Catholic Reformation.
Step-by-step explanation:
The correct response to how the Roman Catholic Church reacted to the spread of Protestantism is option A) Pope Paul Ill convened the Council of Trent. This council was a pivotal part of the Catholic Reformation, which aimed to counter the challenges and doctrinal issues brought up by the Protestant Reformation. The Council of Trent, which met intermittently between 1545 and 1563, aimed to reform the Church from within and reaffirmed its core doctrines, including the importance of both faith and works for salvation, the belief in the existence of Purgatory, the significance of all seven sacraments, the value of religious art, and the authoritative standing of scripture alongside Church traditions and teachings.