Economic mobility in the United States is

A. uncommon. Over 50 percent of poor families remain poor for 8 or more years.
B. uncommon. Over 75 percent of poor families remain poor for 8 or more years.
C. common. Fewer than 3 percent of poor families remain poor for 8 or more years.
D. common. Fewer than 1 percent of poor families remain poor for 8 or more years.