Which of the following is a correct statement?

a. When an event causes an employee’s withholding allowances to increase, the employee must file a new Form W-4 to avoid being under withheld.

b. Employees file their completed Form W-4s with the IRS.

c. When completing the Deductions and Adjustments Worksheet, an employee with no adjustments to income adds any additional standard deduction to the excess of the employee’s itemized deductions over the employee’s basic standard deduction.

d. A negative net reduction on the Deductions and Adjustments Worksheet reduces the number of the employee’s withholding allowances.