Which of the following was an important element in the growth of political machines

Political machine, in U. S. politics, a party organization, headed by a single boss or small autocratic group, that commands enough votes to maintain political and administrative control of a city, county, or state.

The rapid growth of American cities in the 19th century, a result of both immigration and migration from rural areas, created huge problems for city governments, which were often poorly structured and unable to provide services. In those conditions, political machines-such as Tammany Hall, run by boss William Magear Tweed (1823-73) in New York City-were able to build a loyal voter following, especially among immigrant groups, by performing such favours as providing jobs or housing.