Who is considered an "arriving alien"?

An "arriving alien" is specifically defined as an individual who is seeking admission to the United States at a port of entry or who is undergoing inspection by immigration authorities. The correct choice, which refers to a person subject to expedited removal procedures at a U.S. port of entry, aligns with this definition. An "arriving alien" is not yet admitted to the United States, and their status is evaluated at the point of entry.

The other options do not fit this definition. A U.S. citizen traveling abroad does not fall under the category of an arriving alien since they are not subject to the immigration admission process; they are recognized as citizens upon their return. An individual with temporary work authorization is already in the U.S. and holds a valid immigration status, thus not considered an "arriving alien." Similarly, a lawful permanent resident returning home is returning to a status they already hold and is neither seeking admission nor going through the inspection process in the same way that an arriving alien would be.