A firm wants to find out the ridership in USA for a few of it car, the firm divides USA into 30 regions, of which 10 region are chosen randomly. The team then randomly chooses several housing unit of each region, followed by picking a simple random sample of household within those blocks Which Sampling method best describes their method?
1) Systematic
2) Simple random
3) cluster
4)Stratified
5)Multi-stage