There are five regions in a politician's area but redistribution has been proposed for the state. The politician would like to know which region he should try to remove from his electorate to givr him the best advantage after the redistribution. He plans to conduct a survey to find out his approval rating.

Which one of the following sampling plans would be most useful for his purposes?

a.Take a stratified sample with political parties as the strata.

b.Take a stratified sample with the five regions as the strata.

c.Take a simple random sample across his district.

d.Take a cluster sample with the five regions as clusters.