Hi to all,
this question has definately caused a wide spread of answers, so here is the expaination.
Aluminum wiring: commonly found in MH from 1964-1975
Polybutelyne plumbing: commonly found in MH fom mid 1960-current
Drywall: not normally used in MH until the late 1990’s, paneling was the norm
Plywood flooring: was and is the most common floor material for MH
So the correct answer is: