Which of the following can classify an individual as a qualifying child for tax purposes?

To classify an individual as a qualifying child for tax purposes, certain criteria must be met, and being disabled at any age while living with the taxpayer is one of them. This provision allows for flexibility in the age requirement for qualifying children; typically, a qualifying child must be under the age of 19, or under 24 if a full-time student. However, there is no age limit for individuals who are permanently and totally disabled.

This means that if an individual who is permanently disabled resides with the taxpayer, they can still meet the criteria to be considered a qualifying child regardless of their age. This is crucial as it acknowledges and provides support for families caring for disabled dependents, allowing taxpayers to potentially claim tax benefits that may be available for such eligible dependents.

Regarding the other options, living with the taxpayer for less than half the year fails to meet one of the key residency requirements for a qualifying child, being a full-time student aged 25 exceeds the maximum age limit unless they're disabled, and filing a joint return with a partner typically disqualifies a child unless there are special circumstances. Hence, option C stands out for aligning with the established guidelines for classifying someone as a qualifying child.