The purpose of the Council of Trent was to…
a. translate the Bible into the vernacular.
b. spread the Catholic faith to distant lands.
c. direct the reform of the Catholic Church.
d. fight Protestantism by rooting out heresy.
The purpose of the Council of Trent was to "d. fight Protestantism by rooting out heresy," since the Protestants had been rallying against the Church for quite some time by this point.