D. A historian reads a journal entry by a pilgrim.
Yes, it is true that linguists do not know for certain how language was developed by early humans, but they're able to determine that it started somewhere in Africa, due to human migration patterns.
We (as in 2016) cannot use the land bridge because of the melting of the glaciers. Back then the glaciers were still in one piece and the sea levels were much lower than now. This allowed the early people to cross the bearing straight.
A type of civilization called Harrapa
