单选题：根据下面资料，回答题 To produce the upheaval in the United States that

根据下面资料，回答题
To produce the upheaval in the United States that changed and modernized the domain of higher education fromthe mid-1860' s to the mid-1880' s, three primary causes interacted. The mergence of a half-dozen leaders in educa-tion provided the personal force that was needed. Moreover, an outcry for a fresher, more practical, and more ad-vanced kind of instruction arose among the alumni and friends of nearly all of the old colleges and grew into a move-ment that overrode all conservative, opposition. The aggressive "Young Yale" movement appeared, demanding par-tial alumni control, a more liberal spirit, and a broader course of study. The graduates of Harvard University simul-taneously rallied to relieve the University' s poverty and demand new enterprise. Education was pushing toward high-er standard in the East by throwing off church leadership everywhere, and in the West by finding a wider range ofstudies and a new sense of public duty.
The old-style classical education received its most crushing blow in the citadel of Harvard University, whereDr. Charles Elliot, a young captain of thirty-five, son of a former treasurer of Harvard led the progressive forces.
Five revolutionary advances were made during the five years of Dr. Elliot administration. They were the elevationand amplification of entrance requirements, the enlargement of the curriculum and the development of the electivesystem, the recognition of graduate study in the liberal arts, the raising of professional training in law, medicine,and engineering to a postgraduate level, and the fostering of greater maturity in student life. Standards of admission were sharply advanced in 1872 - 1873 and 1876 - 1877. By the appointment of a dean to take charge of student affairs, and a wise handling of discipline, the undergraduates were led to regard themselves more as young gentlemenand less as young animals. One new course of study after another was opened up--science, music, the history of thefine arts, advanced Spanish, political economy, physics, classical philology, and international law.
The passage mainly deals with _______. A．innovations in the United States' s higher education in the late 1800s
B．Harvard University graduates' success
C．the development of Harvard University
D．the aggressive "Young Yale" movement