The correct answer is A. Scaffolding.
Scaffolding is a temporary rigid structure having platforms to enable masons to work at different stages of a building. It is used to provide a safe and stable working platform for workers to access and work at different heights. Scaffolding can be made from a variety of materials, including wood, metal, and plastic. It is typically erected by professional scaffolders, but can also be assembled by experienced DIYers.
B. Dead shore is a type of support used in construction to prevent a structure from moving or collapsing. It is typically made from a large, heavy object, such as a concrete block or a steel beam, and is placed against the structure to provide support.
C. Raking shore is a type of support used in construction to prevent a structure from leaning or falling over. It is typically made from a long, slender beam that is angled against the structure to provide support.
D. Under pinning is a type of support used in construction to prevent a structure from sinking into the ground. It is typically made from a series of concrete piers or piles that are driven into the ground beneath the structure to provide support.