Final answer:
Rental income earned from renting a residence for less than 15 days during the year can be excluded from gross income.
Step-by-step explanation:
When a residence is rented for less than 15 days during the year, the rental income is indeed excluded from gross income. This provision is part of the U.S. tax code and allows homeowners a special exclusion when renting out their property for a very short period, such as during a special event. This rule helps to simplify tax reporting requirements for individuals who do not regularly rent out their property.