Final answer:
An account is part of the financial system described by its title, debit and credit sides, but it is not a source document; rather, it summarizes transactions.
Step-by-step explanation:
An account in the context of financial information systems is described by all except option c: an account is a source document. An account is not a source document; rather it is a record that summarizes the transactions affecting it. An account typically does consist of three parts: the title, the debit side, and the credit side. In the format of a T-account, which represents a balance sheet, assets are listed on the debit side and liabilities on the credit side, encapsulating the fundamental accounting equation that assets equal liabilities plus owner's equity. Transaction costs would be associated with making entries into accounts due to activities such as finding a lender or a borrower for money.