A New Product Is Being Introduced, and a Nationwide Survey

A new product is being introduced, and a nationwide survey to determine the public's opinion of the product is to be conducted. The country is divided into six regions, then two states are randomly selected from each region, and then each state is divided into rural and urban markets. A number of these markets are selected, and randomly selected people is these markets are surveyed about the new product. What type of sampling technique is being employed here?

A) sequence sampling
B) double sampling
C) multistage sampling
D) systematic sampling