A Student Scoops a Bucket of Water and Sediment from the Side

A student scoops a bucket of water and sediment from the side of a stream. A second student scoops a bucket of water and sediment from the center of the stream. What is the most probable outcome?

A) The first student would have large rocks and boulders because the stream flow sweeps these out of the way and to the sides. The second student might have small rocks and pebbles because the stream wears the rocks down where it flows quickly in the middle.
B) The first student would have mud and small rocks because the stream flows slowly at the sides. The second student might have mostly mud because mud settles to the bottom.
C) The first student would have mud and small rocks because the stream flows slowly at the sides. The second student might have large rocks and pebbles because the stream probably flows more quickly in the middle.
D) The first student would have mud and medium-to-large size rocks that get stuck in the mud at the sides. The second student might have pebbles.