Owners of a radio station want to obtain information on the online radio listening habits in Spain. The station sends a survey out to those listeners with email addresses. Which of the following sampling designs best represents the type of survey design described?

A cluster sample using the cities in clusters

A convenience sample from the entire country

A simple random sample from the entire country

A stratified sample from the entire country

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