Which of the following is an example of a search that can be performed upon entry and exit?

A border search is specifically designed to enhance security at international borders and ports of entry. This type of search is authorized by law and does not require a warrant or probable cause due to the government's interest in protecting its borders. Border searches can be conducted on individuals and their belongings as they enter or exit the country, making them distinct from other types of searches which may require judicial oversight or consent.

In contrast, a search warrant typically involves a judge's approval based on probable cause, and is generally executed at a specific location rather than being tied to the act of crossing a border. A consent search occurs when an individual voluntarily allows a law enforcement officer to conduct a search, which also does not apply to the automatic nature of searches performed at borders. Lastly, a search during a lawful stop usually entails an encounter where the officer has a specific legal reason to stop the individual, and does not universally apply to the entry or exit context as border searches do.