The correct answer is: A. Shoring.
Shoring is a temporary support system used to prevent the collapse of an unsafe structure. It is typically made up of vertical posts and horizontal beams that are braced against the structure. Shoring can be used to support a variety of structures, including buildings, bridges, and retaining walls.
Scaffolding is a temporary platform that is used to access and work on a structure that is too high to reach from the ground. It is typically made up of a series of platforms that are supported by vertical posts and horizontal beams. Scaffolding can be used for a variety of purposes, including painting, repairing, and cleaning.
Underpinning is a technique that is used to support the foundation of a structure that is sinking or settling. It involves digging a trench around the foundation and then installing new support piers or walls. Underpinning can be used to save a structure that is in danger of collapse.
Jacking is a technique that is used to lift a structure that has settled or is sinking. It involves installing hydraulic jacks under the structure and then using the jacks to lift the structure. Jacking can be used to level a structure or to prevent it from collapsing.
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