The correct answer is C. Mortar.
Mortar is a thick paste of cement, sand, and water. It is used to bind bricks, stones, and other masonry units together. Mortar can also be used to fill
in gaps between masonry units.Concrete is a mixture of cement, sand, gravel, and water. It is a hard, durable material that is used in
construction for a variety of purposes, such as building foundations, roads, and bridges.R.C.C. is reinforced concrete. It is a composite material that consists of concrete and steel reinforcement. R.C.C. is stronger than concrete alone and is used in construction for a variety of purposes, such as building high-rise buildings and bridges.
Kiln is a furnace used for firing pottery, bricks, and other materials. It is typically made of brick or stone and is heated by burning coal, wood, or other fuel.