The fact that an employee is having taxes withheld from their paycheck does not guarantee that their tax liability will be covered. What factor could cause an employee to have a withholding shortfall at the end of the year? O The taxpayer neglected to include student loan interest that would be paid during the year when completing Form W-4. O The taxpayer included too few allowances on their 2021 Form W-4. O The taxpayer filed their income tax return after the deadline O Additional income was earned from self-employment.