Final answer:
Any taxpayer can use their respective tax rate schedule for calculating taxes on their taxable income, adhering to the progressive tax system where rates increase with income.
Step-by-step explanation:
The question pertains to which taxpayer category can use the tax rate schedule to calculate their taxable income without the need for additional computations for different types of income. All of the listed taxpayer types—single taxpayers, head of household taxpayers, married filing jointly taxpayers, and married filing separately taxpayers—use different tax rate schedules that are specifically tailored to their filing status. This means that any taxpayer, regardless of filing status, can use their respective tax rate schedule to calculate the tax on their taxable income. It is important to note that the income tax is a progressive tax, where rates increase with the level of income, and they are also influenced by factors such as marital status and family size.