Which document summarizes a taxpayer's income from employment?

The correct choice summarizes a taxpayer's income from employment through the use of Form W-2. This document is issued by employers to their employees and includes crucial information such as the total wages earned during the tax year and the amount of taxes withheld. Each employee receives a W-2 form, which they use to report their income on their individual tax return. This form not only reflects the gross salary but also provides details on various tax withholdings, enabling the taxpayer to calculate their tax liability accurately.

Other forms mentioned serve different purposes. For example, Form 1099 is typically used for reporting income received from sources other than an employer, such as freelance work or interest payments. Form 1040 is the actual income tax return form where taxpayers report their overall income and calculate their tax liability. Form 4506-T is not related to income reporting; instead, it is a request for a transcript of tax returns. Thus, the choice of Form W-2 is essential as it directly summarizes employment-related income.