Owners of a radio station want to obtain information on the satellite radio listening habits in the state of Washington. The station splits up the star by cities and selects people randomly to survey from each city. Which of the following sampling designs best represents the type of survey design described?

a cluster sample using the cities as clusters

a convenience sample from the entire state

a simple random sample from the entire state

a stratified sample from the cities in the state

an online poll that invites all people from the cities and towns in the market area to participate