单选题：回答题：The United States perceives itself to be a middle-class

回答题：
The United States perceives itself to be a middle-class nation, However, middle class is not a real designation,nor does it carry privileges. It is more of a perception, which probably was as true as it ever could be right after World War II. The economy was growing,more and more people owned their own homes,workers had solid contracts with the companies that employed them, and nearly everyone whowanted a higher education could have one. Successful people enjoyed upward social mobility. They may have started out poor,but they could become rich. Successful people also found that they had greater geographic mobility. In other words,they found themselves moving to and living in a variety of places.
The middle class collectively holds several values and principles. One strong value is the need to earn enough money to feel that one can determine one's own economic fate. In addition,middle class morality embraces principles of individual responsibility, importance of family, obligations to others,and believing in something outside oneself.
But in the 1990s those in the middle class found that there was a price for success. A U. S. News & World Report survey in 1994 indicated that 75 percent of Americans believed that middle class families could no longer make ends meet. Both spouses now worked,as did some of the children; long commutes became routine; the need for child care put strains on the family; and public schools were not as good as they once were. Members of the middle class were no longer financing their lifestyles through earnings but were using credit to stay afloat. The understanding of just what middle class meant was changing.
The information in this passage deals with A．an individual
B．a social and economic group
C．a political organization
D．government