Correct Option: A

P-2, Q-4, R-1, S-5
Scaffolding is a temporary platform constructed for reaching heights above arms' reach for the purpose of building construction, maintenance, or repair. It is usually made of lumber and steel and can range from simple to complex in design, depending on its use and purpose.
Formwork is another term for shuttering. Formwork is a structure, usually temporary, used to contain poured concrete and to mould it to the required dimensions and support until it is able to support itself. It consists primarily of the face contact material and the bearers that directly
Shoring is a general term used in construction to describe the process of supporting a structure in order to prevent collapse so that construction can proceed. It can be done with the help of shores or props.
They can be used under the following circumstances :
1. When walls bulge out
2. When walls crack due to unequal settlement of foundation and repairs are to be carried out to the cracked wall.
3. When an adjacent structure needs pulling down.
4. When openings are to be newly made or enlarged in a wall.
Underpinning is a method used t o increase foundation depth or repairing faulty foundations. This might be the case if you plan to add stories to an existing structure or when the foundation has been damaged. One visible sign that a building needs underpinning are cracks appearance. When a building needs a foundation repair some cracks, especially wider than ¼ inch appear visible, meaning than an underpinning needs to be done.
Foundation failures could also be considered as heaved foundations, cracked or buckled walls and cracked concrete floors.