If a National Political Pollster Selects Ten States Randomly,then Randomly

Multiple Choice

If a national political pollster selects ten states randomly,then randomly selects five counties within each state,then randomly selects five voting precincts within these counties,then randomly selects five blocks within these precincts,then randomly selects five households for door-to-door interviews about their voting intentions in the next Presidential election,this is an example of what type of sampling procedure?

A) simple random sample
B) multistage area sample
C) systematic sample
D) nonprobability sample