which of these is not a source of revenue for political parties?

The source of revenue for political parties that is not listed here is "tolls". Tolls refer to fees that are charged for the use of particular roads or highways. This source of revenue is typically collected by governments or private companies that own and maintain the roads, and it is not typically used to fund political parties. On the other hand, political parties can generate revenue through dues, grants, and donations. Dues are fees that party members pay to support the party, while grants are funds provided by governments or other organizations to support specific programs or initiatives. Donations are voluntary contributions made by individuals, businesses, or organizations to support the party. In summary, while dues, grants, and donations can all be sources of revenue for political parties, tolls are not typically used in this way.