Answered

William J. Levitt helped the expansion of the American suburbs by

Aintroducing mass-produced housing developments
Bcreating the Federal Housing Administration
Cdesigning an interstate highway system
Destablishing the installment plan
Ecreating an improved mass-transit system

Verified Answer :

William J. Levitt helped the expansion of the American suburbs by "(A) introducing mass-produced housing developments" since these developments were relatively affordable, especially for returning veterans.