Which of the following was a consequence of the collapse of the Western Roman Empire?

The Byzantine Empire flourished.

The Roman Catholic and Eastern Orthodox Churches merged.

The Byzantine Empire adopted Christianity as the official religion.

The Byzantine Empire collapsed.

The correct answer should be The Byzantine Empire flourished. The Byzantine empire adopted Christianity while it was still Roman empire and the religions didn't merge but rather went their own ways, splitting into Orthodoxy and Catholicism, former in the east latter in the west. The Byzantine empire flourished and became one of the strongest powers in the world.