Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 40 to 46.

At the beginning of the nineteenth century, the American educational system was desperately in need of reform. Private schools existed, but only for the very rich. There were very few public schools because of the strong sentiment that children who would grow up to be laborers should not “waste” their time on education but should instead prepare themselves for their life’s work. It was in the face of this public sentiment that educational reformers set about their task. Horace Mann, probably the most famous of the reformers, felt that there was no excuse in a republic for any citizen to be uneducated. As Manager of Education in the state of Massachusetts from 1837 to 1848, he initiated various changes, which were soon matched in other school districts around the country. He extended the school year from five to six months and improved the quality of teachers by instituting teacher education and raising teacher salaries. Although these changes did not bring about a sudden improvement in the educational system, they at least increased public awareness as to the need for a further strengthening of the system.

The word “they” in the passage refers to _______ .