A researcher studied Community Oriented Policing $($COP$)$ programs in all major U$.$S$.$ cities to see if they were effective in preventing crime. The police administrator filling out the survey was asked to provide information specific to his$/$her department$$s COP program. The unit of analysis was: A$.$ major U$.$S$.$ cities. B$.$ crime rates. C$.$ police officers. D$.$ COP programs.