During a flood, a mountain stream is carrying clay, silt, sand, and pebbles. The streambed and particle sizes are shown below. Which sediments will most likely be deposited first when the stream slows down? A. Pebbles
B. Sand
C. Silt
D. Clay

The clay because it has the smallest particles size.

Pebbles

Explanation:

The faster a stream flows, the larger the particles it can carry. When the current slows down the largest particles will be deposited first, which in this case are the pebbles. If the stream continues to slow down the sand will be deposited next, followed by the silt and clay. (Clay is only deposited when the water is nearly still.)