[单项选择]台湾蓝领阶级的下层人员人数达到：（）
A. 150万
B. 200万
C. 300万
D. 400万

Political controversy about the public-land policy of the United States began with the America Revolution. (1) , even before independence from Britain was (2) , it became clear that (3) the dilemmas surrounding the public domain might prove necessary to (4) the Union itself.
At the peace negotiation with Britain, Americans obtained a western (5) at the Mississippi River. Thus the new nation secured for its birthright a vast internal empire rich in agricultural and mineral resources. But (6) their colonial charters, seven states claimed (7) of the western wilderness. Virginia’s claim was the largest, (8) north and west to encompass the later states. The language of the charters was (9) and their validity questionable, but during the war Virginia reinforced its title by sponsoring Colonel Georgia Rogers Clark’s 1778 (10) to Vicennes and Kaskaskia, which (11) America’s tra
A. obvious
B. dismal
C. gloomy
D. vague