Which of the following statements below best characterizes american households?

a. young college graduates are moving back into their parents’ homes in unprecedented numbers, as they face bleak job prospects.

b. the number of americans living in multigenerational households has been declining for several decades.

c. the declining immigrant population has contributed to the decline in multigenerational households.

d. the number of grandparents living with and raising their grandchildren has declined steadily since the 1990s.