The underlined word "profess" in the fourth paragraph most likely means ______.

A．professors with academic achievements are usually responsible and tough
B．it is difficult to conduct objective evaluation of teaching quality
C．top students who want to be challenged appreciate research professors
D．research helps to improve the effectiveness of teaching

A．is a desirable result of economic development
B．brings about greater opportunities for land dealers
C．lead to an efficient, positive use of land in the form of vertical growth
D．is annoyingly artificial and meaningless