Which of the following is NOT a criterion for claiming a dependent?

The criterion regarding enrollment in school full-time is not a requirement for claiming a dependent. To qualify as a dependent under IRS guidelines, a person must meet specific conditions, but full-time student status is not one of them.

The main criteria include that the dependent must be a citizen, national, or resident of the U.S. or a resident of Canada or Mexico, ensuring that the tax benefits are directed toward individuals primarily in the U.S. system. Additionally, the dependent typically needs to reside with the taxpayer for more than half the year, which reinforces the idea of a significant shared household. Finally, a dependent must not provide more than half of their own support, indicating that the taxpayer is contributing to the dependent's financial well-being.

These three criteria are foundational for establishing the eligibility of a person to be claimed as a dependent, while full-time enrollment in school, although it may apply in some situations (e.g., qualifying for the child tax credit for children over 17), is not a standalone requirement for dependency claims.