Answer:
B - Those affected by the dust bowl that hit the great plain (which comprised of mostly farmers and sharecroppers) had to migrate to California as well as other States of the United States in search for work and other opportunities after suffering the effect of their over farming practices which culminated in the Dust Bowl.
Explanation:
The Dust Bowl of 1930s was an era when dust storm, erosion, and drought destroyed the topsoil and devastated the ecology and agricultural practices in the great plain as a result of over-farming practices of farmers ad sharecroppers. This period witnessed the highest migration from the great plain to California as farmers and sharecroppers whose farms and agricultural products had been destroyed by the Dust Bowl had to migrate for greener pastures.