Final answer:
Form 945 is used to report backup withholding to the IRS, which is different from forms related to payroll and unemployment taxes.
Step-by-step explanation:
The correct form to report backup withholding is Form 945. A household or firm may encounter the need to use Form 945 to report any backup withholding to the IRS. Backup withholding can occur in various situations, such as when a taxpayer fails to provide a correct taxpayer identification number (TIN) to a payer. This form is annually filed to report the withholding from non-payroll sources. In contrast, forms like Form 940 and Form 941 are related to federal unemployment tax and payroll taxes, respectively. It’s important for firms to use the appropriate tax forms to report different types of taxes or withholdings to ensure financial responsibility and compliance with the U.S. tax code.