Answer:
D. a percentage of their salaries
Step-by-step explanation:
This is based on the spoil system which explains or is been described as a system where campaign workers of the sitting government are been offered civil service positions as compensation to their endeavours during the campaigns/rally. This is sometimes referred to as the patronage system too. That is why jobs and government positions gained through this system are expected to contribute a percentage of their salaries. Changes in party that are in control of government sometimes also brings new government workers carrying political responsibility.