What inspired Roman Catholic social reformers at the turn-of-the-century in the United States, Europe, and Latin America?

A) the social gospel
B) Pope Leo XIII's Rerum novarum
C) the unification of Italy
D) the persecution of Catholics in the Russian Empire

Pope Leo XIII's encyclical Rerum novarum, issued in 1891, was a foundational text for Catholic social teaching, addressing the conditions of the working classes and calling for social reform in response to the challenges posed by industrialization and capitalism. This document inspired Catholic social reformers across the United States, Europe, and Latin America.