All of the Following Help Explain the Rise of Suburbia

All of the following help explain the rise of suburbia EXCEPT

A) "white flight," which lured rural residents to the glamour and high living standards of metropolitan areas.
B) the "baby boom," which led to a large number of young families seeking their own houses.
C) the availability of affordable single-family houses on their own lots.
D) the availability of transportation, which made commuting to a job elsewhere possible.