Which of the following is a type of proprietary fund?

Internal Service Funds are categorized as proprietary funds because they operate similarly to private business enterprises. These funds are used by government entities to account for goods and services provided to other departments or agencies within the same government. They operate on a full accrual basis, which means that they recognize revenues when they are earned and expenses when they are incurred, just like a business.

The primary goal of Internal Service Funds is to charge users for the services provided, essentially allowing governments to recuperate the costs incurred, enabling efficiency in service delivery. This fund type often includes functions such as fleet services, technology support, and risk management services, where the costs are billed to other departments in the government, allowing for a clearer picture of each department's expenses and promoting accountability.

In contrast, Debt Service Funds, Special Revenue Funds, and Permanently Restricted Funds serve different purposes and follow different accounting practices, as they are more focused on specific revenue sources and spending parameters rather than operating like a business.