Moraines are landforms that are formed in glacial regions. Glacial regions are areas where glaciers exist, which are huge masses of ice that move very slowly. As the glacier moves along the land, it picks up rocks, soil, and debris, which get transported with the ice. When the glacier begins to melt, it deposits this material in the form of moraines.
Option-1: River deltas are landforms formed at the mouth of a river where it meets a body of water, such as an ocean or a lake. Moraines are not formed in river deltas.
Option-2: Arid regions are dry and barren areas with little to no vegetation. Moraines are not formed in arid regions.
Option-4: Monsoon regions are characterized by seasonal heavy rainfall. Moraines are not formed in monsoon regions.
Therefore, the correct answer is option 3 - Glacial regions.