Once the ocean forms in the rift valley, the split continent represents how many lithospheric plates?

The forming of the ocean in the rift valley will result into the split continent representing two lithospheric plates.

Explanation:

The continent would split into two plates named as Somali plate and the Nubian plate. As the extension of the split continues, the lithospheric rupture will occur within 10 million years. This will result in forming of a new ocean basin. This split of continent is currently being experienced in the African continent.