Here's why:

* Moraine: A moraine is a landform composed of till, unsorted glacial debris, that is deposited by a glacier. It's the direct result of deposition.

Let's look at the other options:

* Cirque: A cirque is a bowl-shaped hollow formed by glacial erosion, not deposition.

* Arete: An arete is a sharp, jagged ridge formed by glacial erosion from two opposing cirques.

* U-shaped valley: A U-shaped valley is formed by the erosive power of a glacier carving out a valley with steep sides and a flat bottom.

In summary, moraines are the only glacial feature directly formed by deposition.