What might cause an employee's withholding amount to change?

The correct answer is the change in personal circumstances. An employee's withholding amount is directly influenced by various personal factors such as marital status, number of dependents, and any additional tax benefits or deductions they may claim. For example, if an employee gets married or has a child, they may adjust their withholding allowances on their W-4 form, potentially resulting in a change to the amount withheld from their paycheck. Similarly, if an employee experiences a significant life event, such as a divorce or a change in dependent status, these circumstances can lead to adjustments in their withholding to align with their updated tax obligations.

While changes in job title or work hours may impact an employee's overall earnings, they do not inherently alter the tax withholding calculations unless they also influence personal tax situations. For instance, a promotion may increase salary but does not affect withholding unless the individual also decides to modify their W-4 based on personal changes.