In the early nineteenth century, settlers of the American West passed through the Great Plains. Which statement about their experiences is correct?
A.
The mountainous terrain of the Great Plains was difficult to travel across.
B.
The plains provided food to feed the animals that pulled the settlers' wagons.
C.
Icy winds meant that travelers could only cross the Great Plains in the summer.
D.
The plains were unpopulated and travelers encountered very few American Indians.