What was a reform that Pope John XXIII's Vatican II council introduced into the Catholic Church?

A) allowing the Mass to be said in local languages instead of Latin alone
B) making changes in the Church's dogma about marriage
C) recognizing the Church's failure when confronted with the Holocaust
D) appointing more cardinals from European nations
E) renewing the Counter Reformation

Vatican II Council

The Second Vatican Council, a major meeting of the Roman Catholic Church (1962-1965) that introduced significant changes in Church practices and approaches to worship and engagement with the modern world.

Pope John XXIII

The head of the Roman Catholic Church from 1958 to 1963, known for convening the Second Vatican Council, which introduced significant reforms to modernize the Church.