题目内容：
Questionsare based on the following passage．
Economic inequality is the "defining challenge of our time," President Barack Obama declared in aspeech last month to the Center for American Progress．Inequality is dangerous, he argued, not merelybecause it doesn't look good to have a large gap between the rich and the poor, but because inequalityitself destroys upward mobility, making it harder for the poor to escape from poverty．"Increasedinequality and decreasing mobility pose a fundamental threat to the American Dream," he said．Obama is only the most prominent public figure to declare inequality Public Enemy No．1 and thegreatest threat to reducing poverty in America．A number of prominent economists have also arguedthat it's harder for the poor to climb the economic ladder today because the rungs (横档 ) in that ladderhave grown farther apart．
For all the new attention devoted to the 1 percent, a new damset from the Equality of OpportunityProject at Harvard and Berkeley suggests that, if we care about upward mobility overall, we're vastlyexaggerating the dangers of the rich —poor gap．Inequality itself is not a particularly strong predictor ofeconomic mobility, as sociologist Scott Winship noted in a recent article based on his analysis of this data．So what factors, at the community level, do predict if poor children will move up the economicladder as adtdts? what explains, for instance, why the Salt Lake City metro area is one of the 100largest metropolitan areas most likely to lift the fortunes of the poor and the Atlanta metro area is oneof the least likely?
Harvard economist Raj Cherty has pointed to economic and racial segregation, community density,the size of a community's middle class, the quality of schools, commtmity religiosity, and familystructure, which he calls the "single strongest correlate of upward mobility．" Chetty finds thatcommunities like Salt Lake City, with high levels of two-parent families and religiosity, are much morelikely to see poor children get ahead than communities like Atlanta, with high levels of racial andeconomic segregation．Chetty has not yet issued a comprehensive analysis of the relative predictive power of each of thesefactors．Based on my analyses of the data．of the factors that Chetty has highlighted, the followingthree seem to be most predictive of upward mobility in a given community:
1．Per-capita (人均) income growth
2．Prevalence of single mothers ( where correlation is strong, but negative)
3．Per-capita local government spending In other words, communities with high levels of per-capita income growth, high percentages oftwo-parent families, and high local government spending-which may stand for good schools-are themost likely to help poor children relive Horatio Alger's rags-to-riches story．
How does Obama view economic inequality? A．It is the biggest obstacle to social mobility．
B．It is the greatest threat to social stability．
C．It is the No．1 enemy of income growth．
D．It is the most malicious social evil of our time．
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