The correct answer is Option 1: Stalagmite. A depositional landform refers to a landform that is formed by the deposition or settling of sediment or other materials. In the case of stalagmites, these are rock formations that extend upwards from the floor of a cave.

Stalagmites are formed through a process known as mineral precipitation. As water from the cave ceiling drips down, it carries with it dissolved minerals. Over time, these minerals collect and solidify, causing the stalagmite to grow upwards. Stalagmites can take many different shapes and sizes depending on the specific conditions within the cave, including the type of minerals present and the rate at which water drips down.

It`s important to note that while options 2, 3, and 4 (Lapis, Sinkhole, and Cave) are all related to cave formations, they are not specifically considered depositional landforms. Lapis refers to a type of gemstone that can sometimes be found in caves, sinkholes are formed through the collapse of the ground surface, and caves themselves are typically considered erosional landforms as they are formed through the dissolution of rock by water.