Final answer:
The transaction between the city's mass transit bus system and the city's main operating fund affects the General Fund and the Enterprise Fund. The General Fund is the city's main operating fund, whereas the Enterprise Fund is used for business-like activities, including public services that recover costs through user charges.
Step-by-step explanation:
When a city's mass transit bus system receives an operating transfer from the city's main operating fund, the funds affected by this transaction would primarily be the General Fund and the Enterprise Fund. The General Fund is the main operating fund for a city, often used to account for services financed from general taxation. An Enterprise Fund, on the other hand, is used for operations that are financed and operated in a manner similar to private business enterprises, such as a city's bus system where the intent is that the costs (expenses, including depreciation) of providing services to the public on a continuing basis be financed or recovered primarily through user charges.
Therefore, the correct answer to which fund(s) are affected by this transaction is both b) General Fund and a) Enterprise Fund. The Special Revenue Fund and Internal Service Fund are not directly related to this transaction as they serve different purposes, with the former accounting for specific revenue sources that are restricted or committed to expenditure for specific purposes other than debt service or capital projects, and the latter typically being used to account for the financing of goods or services provided by one department to other departments on a cost-reimbursement basis.