The correct answer is B) a stratified sample.
This action is an example of a stratified sample.
The government of Virginia is about to decide on smoking in public places. So first, a public opinion poll in Virginia wants to determine whether registered voters in the state approve of a measure to ban smoking in all indoor restaurants in the interest of public health. To do so, the government ask the researchers to select a simple random sample of 50 registered voters from each county in the state and ask whether they approve or disapprove of the measure. A stratified sample is a method of sampling in that total population is divided into smaller groups. Then, the researcher randomly picks the participants in the sample. it helps to get information from different subgroups.
The other options of the question were A) a systematic county sample, C) a multistage sample, and D) a simple random sample.