Answer:
Correct answer is Catholic cardinals who wanted to reform the Church.
Explanation:
Lutheran ministers were not present at the council of Trent. Lutheranism was a new belief that was totally different that the beliefs of Catholic Church. Therefore, as the council was called by the Church they didn't participate in it.
Catholics cardinals is the only correct answer as leaders of the church realized that changes had to be introduced if the church wants to preserve its authority.
German princess is also not correct answer as after the treaty of Augsburg certain rules were established regarding their role.
Last option is also not correct as Calvinists were also Protestants.
