Which taxpayer is potentially eligible to receive the Child Tax Credit? In each scenario, the child mentioned is the taxpayer's only dependent or potential dependent, and the taxpayer provided more than half the child's support.

-Ana has a daughter, Isabella, who was 8 years old at the end of 2021. Isabella lived in Mexico for all of 2021 and is not a U.S. citizen, U.S. national, or U.S. resident alien.

-Mariana has a niece, Victoria, who was 10 years old at the end of 2021. Victoria is not a citizen of the United States. Victoria does have an Individual Taxpayer Identification Number (ITIN), and she lived in Mexico for all of 2021.

-Simon has a nephew, Tristan, who is a resident alien. Tristan was 16 years old at the end of 2021. Tristan lived with Simon all year. Tristan obtained a social security number valid for employment before the due date of the return.

-William has a son, Oliver, who was 18 years old at the end of 2021. Oliver is a citizen of the United States and qualifies as a dependent on William's 2021 tax return.