The most significant aspect of the population changes in the United States during the first quarter of the 20th century was the reversal of the earlier movement of population from east to west
continued and rapid growth of cities
mass movement to suburbia
general increase in back-to-the-farm movement

macon. i believe thats the answer

sorry if im wrong.

is there answer chooses?

the correct answer is:   "   3.6 % " .

          →   the unemployment rate is:   " 3.6 % " .

explanation:

to calculate the "unemployment rate" :

the "unemployment rate"   =

  [# of people unemployed] /   [working age population]   * 100 %   ;

                =   [9 million] / [250 million]     *   100 % ;

    →     note:   the units of "million" cancel out;

                    since:   " {million} / {million} = 1 " ;

                =   (9 / 250)   * 100 %   ;

                = 0.036 * 100 % ;

                =   3.6 %

answer:   the unemployment rate is:   " 3.6 % " .