Question

a__________is a flat, triangular - shaped land formed when a river carries and deposits sediment at its mouth.baydeltasoundmouth

Explanation:

To solve this, we analyze each option:

• A bay is a body of water, not a landform formed by sediment deposition at a river's mouth.
• A delta is defined as a flat, triangular - shaped landform created when a river deposits sediment at its mouth, matching the description.
• A sound is a large sea or ocean inlet, not related to river sediment deposition.
• The "mouth" of a river is where it meets another body of water, not the landform described.

Answer:

B. delta