Select the scenario which is an example of voluntary sampling.

. Aninternational airline wants to study the demand for its services. They group their destinations into regions, randomly select 20 of these regions, and study avery "~ destination in each of the selected regions. Cr A'magazine wants to write a story about its readership's eating habits and asks readers to send in their responses to the question "How often do you eat fast food?\" O A supermarket wants to study the buying habits of its customers. They choose every 207" customer entering the supermarket to fill out the survey. _ City managers want to find out if citizens would support a new community center. They randomly choose telephone numbers from an online phone directory and poll O ~ them