Final answer:
A taxpayer's 22-year-old full-time student adopted child does not qualify for the Child Tax Credit (CTC), but may qualify as a Qualifying Child (QC) for other tax benefits, provided that other criteria are also met.
Step-by-step explanation:
The question pertains to whether a taxpayer's adopted child, who is age 22 and a full-time student, qualifies for the Child Tax Credit (CTC) or the Qualifying Child (QC) or Qualifying Relative (QR) for other tax benefits. When considering the expanded CTC laid out in the American Rescue Plan, it is important to note that this credit is available for children under the age of 6 at an expanded amount, and reduced amounts for older children up to age 17. Therefore, a 22-year-old would generally not qualify for the CTC. For the purposes of other tax benefits, the definition of a qualifying child typically includes full-time students up to age 24, who are supported by the taxpayer; however, this student being 22 may still be considered under the QC criterion if they meet other relevant tests, such as the relationship, residency, support, and joint return tests.