Final answer:
A basin that forms in a region where the lithosphere has been stretched is most likely a rift basin. Rift basins occur in areas where the Earth's crust is undergoing tensional forces, causing it to crack and create an elongated depression.
Step-by-step explanation:
A basin that forms in a region where the lithosphere has been stretched is most likely a rift basin. Rift basins occur in areas where the Earth's crust is undergoing tensional forces, causing it to crack and create an elongated depression. These basins are often filled with sediments from the surrounding land and can eventually evolve into new oceans or seas.