Horace Mann is often regarded as a pivotal figure in the reform of education in the United States during the 19th century. The correct answer reflecting his contributions would be:
D his pressure on the state legislature provided money to fund new schools and increased teachers' pay.
Mann advocated for public education, emphasizing the need for a formal education system that was funded by the state. He was instrumental in establishing a statewide board of education in Massachusetts and advocated for better training for teachers, improved educational standards, and increased funding for public schools. His efforts laid the groundwork for the modern public education system in the United States.