The answers B,C, and D are correct.
Government is the governing authority of a nation or political unit, whose purpose is to regulate and organize society. The size of the government will vary according to the size of the state and may be local, regional and national. Within a government, there may be many types of political regimes, some that are highly concerned about the freedom and well being of the population such as minimal state - which is when there are few duties for the government and high economic, political and social freedom, and some historically bad government regimes such as tyranny. Despite them, we also have democracy, dictatorship, oligarchy, and so on.
In contemporary times, democracy is considered the most common political regime in governments and also the most demanded by the people. In general the government "good or useful" is elected by the community to remedy its deficiencies and represent its desires as a whole. Common desires are libraries, parks, transportation, schools and other public needs.