The correct answer is "Reformers."
The "men of goodwill" that Gladden describes are the Reformers.
Washington Gladden (1836-1918) was an American politician and social reformer that supported the Social Gospel, in that all Christians must do something to help society, to fight corruption practices and injustices. He wanted to apply Christian teachings to social problems. He wrote the books "Social Salvation" and "Applied Christianity." He was the one to refer the Reformers as "the "men of goodwill."