What is the name of the spacecraft in Aliens?

The spacecraft in Aliens is the USS Sulaco.

The Sulaco is a fictional Conestoga-class light assault carrier operated by the United States Colonial Marine Corps. It transports Ellen Ripley, Lieutenant Gorman, Carter Burke, and the Marine unit to LV-426 to investigate the silent terraforming colony Hadley's Hope.

Much of the film's opening military staging takes place aboard the Sulaco, where Ripley meets the Colonial Marines and the android Bishop. The ship deploys an atmospheric dropship to the planet's surface, allowing the team to reach the colony. After the mission, the surviving characters return to the Sulaco and enter hypersleep.

The other choices belong to different parts of the Alien universe. The Nostromo is the commercial towing vessel from Alien, while Prometheus is the research ship in the 2012 prequel film. Covenant is the colony ship from Alien: Covenant. The Sulaco itself later becomes important in Alien 3, which begins after an escape pod leaves the vessel.