Amy hikes down into the Grand Canyon to see Havasu Falls, a waterfall famous for its blue-green water and rock formations. Amy walks up to the rapidly-flowing river at the waterfall. She observes it is transporting a lot of sediment. What happens to the sediment as it flows downstream? To find out, she goes to the end of the steep canyon where the river becomes wider and shallower. What process takes place as the river slows down?

A. runoff
B. physical erosion
C. deposition
D. chemical weathering