Final answer:
IRS rules for supplemental wage payments dictate that bonuses can be taxed either at a flat supplemental rate or combined with regular wages and taxed according to standard tax brackets. Nico's $6,000 bonus should usually be taxed at 22% if identified separately, which would be $1,320. Without specific tax brackets, it's challenging to specify the incorrect withholding amount from the provided options.
Step-by-step explanation:
The question concerns supplemental wage payments and federal income withholding tax amounts as governed by IRS rules. Supplemental wages can be taxed in different ways, including a flat percentage if they're identified separately from regular wages, or added to the regular pay and taxed according to the usual income tax brackets. The Percentage Method Tables for Manual Payroll Systems with Forms W-4 from 2020 or later are used to calculate taxes on wages and supplemental wages for an employee.
Nico's bonus of $6,000 could be taxed at a flat supplemental rate, which is typically 22% for amounts under $1 million, or it could be added to his regular biweekly wages and taxed according to the regular tax brackets. Given that Nico is single with no dependents and earns biweekly wages of $5,000, the withholding amounts should be consistent with the supplemental wage tax options and the regular tax brackets.
Without the specific tax brackets and withholding percentage applied, it's not possible to definitively identify the incorrect withholding amount from the options provided. However, for 2020 and later, the IRS generally uses a flat 22% rate for supplemental wages under $1 million if withheld separately from regular income, which in Nico's case would be $1,320 ($6,000 x 0.22). If taxes had already been withheld from regular pay, the employer might use a different method such as aggregating the bonus with regular wages and withholding taxes based on the sum using the tax tables.