What is a key requirement for a taxpayer to claim a Child Tax Credit?

To claim the Child Tax Credit, a crucial requirement is that the child must have a Social Security number. This identification number is essential for the IRS to verify the child's identity and eligibility under the guidelines for the credit. The Social Security number helps ensure that tax credits are issued accurately and helps prevent fraud.

The other options do not represent primary requirements for claiming the Child Tax Credit. For instance, a child does not need to be attending school or have a job to qualify for this credit; eligibility primarily concerns the child's age, residency, and support provided by the taxpayer, along with having a valid Social Security number. Additionally, while residency is a factor, it is not mandated that the child resides exclusively with relatives; rather, they must live with the taxpayer for more than half of the year. Thus, the presence of a Social Security number is the most critical factor in securing the Child Tax Credit.