All the residents of a building were polled about whom they would vote for in the upcoming city election for comptroller. What are the sample and the population in this poll?

The population is the registered voters in the city; the sample is the residents of the building.

The population is the residents of the building; the sample is the residents who responded.

The population is the registered voters in the city; the sampleis a random sample of the residents of the building.

The population is the residents of the building; the sample is the registered voters in the city.