Stalactites and stalagmites are geological formations that are found in caves and are typically associated with karst topography. Karst topography is formed by the dissolution of soluble rocks, such as limestone, by acidic water.
A stalactite is a type of formation that hangs from the ceiling of a cave. It is formed when water containing dissolved minerals, usually calcium carbonate, drips from the ceiling and leaves behind deposits that build up over time. The resulting formation often resembles an icicle hanging from the cave ceiling.
On the other hand, a stalagmite is a formation that grows from the floor of the cave. It is formed when the drips from a stalactite or other sources of water hit the floor and deposits the minerals, building up over time. Stalagmites often have a more rounded shape compared to stalactites.
Therefore, based on their formation and association with caves, the correct answer is option 3 - karst topography.