"down the ohio up the mississippi and westward on the missouri river" describes the principal route of which group

The correct answer to this open question is the following.

"Down Ohio up the Mississippi and westward on the Missouri River" describes the principal route of the Seneca and Shawnee.

The Shawnee Indian tribe lived in the area of the Ohio River, but when the Indian Removal Act was enacted in 1830, they had to relocate to the western territories of the Mississippi River, where they intermingle with the Seneca Native American Indian tribe. In December 1932, both tribes signed a cooperation agreement called "the United Nation of Seneca and Shawnee," and settled the Indian Territory of what today is Oklahoma.

i think the answer is   b.