Which document is essential for proving a borrower's income?

The correct answer is the pay stubs, as they provide specific information regarding a borrower's income. Pay stubs detail wages earned, deductions, and the frequency of payments, giving lenders a reliable snapshot of a borrower’s current income situation. They are typically provided from the borrower's employer and serve as direct proof of earnings, which lenders require to assess the borrower's ability to repay the mortgage.

Other documents like bank statements could typically provide indirect evidence of income, but they are not specific enough to accurately reflect a borrower's earnings. While property deeds and credit reports are important documents in the mortgage process, they do not serve the purpose of validating income. The pay stub is specifically designed to show earnings and is therefore the most appropriate choice for verifying a borrower's income.