What Best Describes the Role of Party Machines in Urban

What best describes the role of party machines in urban politics at the turn of the century?

A) Although these political systems thrived on corruption, they also secured access to services for many immigrant and working-class populations.
B) Party machines undermined the principles of democracy by marginalizing immigrants in the electoral process.
C) Although party machines did local communities some service early on, they later became little more than systems of bribery with no benefit to anyone.
D) The political party machine in urban America was essential at a time when parties lacked disciplined organization.