The statistic below shows one area of economic prosperity in the 1950s:

retail record sales in 1954: $182 million
retail record sales in 1960: $520 million

which statement explains a key reason for the rapid rise in record sales in between 1954 and 1960?

the post war population increase
the spread of television to most american homes
the development of rock and roll music
the development of new record production methods