Answer:
4) downward mobility
Explanation:
Downward mobility -
The movement of any group or an individual reduces in term of the status , power or class , is known as the downward mobility .
This case is observed during the period of recession , when people lose their jobs and also the economy collapse , leading to a downward mobility .
hence , same case is given in the question , of the United States , in the year 2008 , therefore , the correct term is 4) downward mobility .