How did Charles end up with Eastman for his last name?

Fifteen years later Ohíyesa was reunited with his father and oldest brother John in South Dakota. The father had converted to Christianity, after which he took the name of Jacob Eastman. John also converted and took the surname Eastman. ... When Ohiyesa accepted Christianity, he took the name Charles Alexander Eastman.

answer; (d) anthropology;

fertile good for trade etc