In the following sentence “Two hundred and twenty-

one years ago, in a hall that still stands across the street, a group of men gathered and, with these simple words, launched America’s improbable experiment in democracy.” By “experiment”, Obama actually means ：

A.The ideal and the attempts of the earlier immigrants to draw up and enact the Constitution so as to establish a democratic country which was free from the divine right of Kings.

B.The efforts the US people made to address the racial issue

C.The American dream

D.The earlier immigrants’ escape from the tyranny and persecution they had in their homeland.