Final answer:
Mackenzie should report her income from the S corporation on Schedule E, Supplemental Income and Loss, as this is used for pass-through entities like S corporations.
Step-by-step explanation:
Mackenzie's income from her share in an S corporation, the family restaurant, should be reported on Schedule E, Supplemental Income and Loss. This form is used for reporting income from pass-through entities, such as S corporations, partnerships, and trusts.
Since Mackenzie does not actively work in the restaurant but receives a Schedule K-1 documenting her share of the income, Schedule E is the appropriate place to report this income on her tax return.
Income from S corporations is passed through to the shareholders and is taxed at their individual income tax rates, and it is not subject to corporate income tax. Unlike C corporations, S corporations do not pay income tax at the corporate level.