Câu hỏi:

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 36 to 42.

          Perhaps it was his own lack of adequate schooling that inspired Horace Mann to work so hard for the important reforms in education that he accomplished. While he was still a boy, his father and older brother died, and he became responsible for supporting his family. Like most of the children in his town, he attended school only two or three months a year. Later, with the help of several teachers, he was able to study law and became a member of the Massachusetts bar, but he never forgot those early struggles.

          While serving in Massachusetts legislature, he signed a historic education bill that set up a state board of education. Without regret, he gave up his successful legal practice and political career to become the frst secretary of the board. There he exercised an enormous influence during the critical period of reconstruction that brought into existence the American graded elementary school as substitute for the older distinct school system. Under his leadership, the curriculum was restructured, the school year was increased to a minimum of six months, and mandatory schooling was extended to age sixteen. Other important reforms included the establishment of state normal schools for teacher training, institutes for in-service teacher education, and lyceums for adult education. He was also instrument in improving salaries for eachers and creating school libraries.

          Mann’s ideas about school reform were developed and distributed in twelve annual reports to the state of Massachusetts that he wrote during his tenure as secretary of education. Considered quite radical at the time, the Massachusetts reforms later served as a model for the nation. Mann was recognized as the  father of public education

The word “mandatory” in line 10 is closest in meaning to