A proof of the equality of debits and credits in a general ledger is known as a(n):

A trial balance is a report that lists the balances of all general ledger accounts at a specific point in time, ensuring that the total debits equal the total credits. This serves as a key internal control tool in accounting, confirming that all entries made in the ledger are mathematically correct. The trial balance is essential for detecting errors in the recording process since any imbalance between debits and credits indicates that there may be mistakes that need to be addressed before preparing financial statements, such as the income statement or balance sheet.

The other options do not serve this specific purpose: an income statement reflects the company's revenues and expenses over a period, a balance sheet shows the company's assets, liabilities, and shareholders' equity at a moment in time, and a cash flow statement focuses on cash inflows and outflows during a period. None of these documents provide a direct proof of the equality of debits and credits in the general ledger.