The correct answer is: C. Columns and struts
Wrought iron is a type of iron that is very strong and ductile. It is made by heating iron ore and then hammering it into shape. Wrought iron is often used for structural works in beams, columns, and struts. It is also used for making decorative items, such as gates and fences.
Option A is incorrect because wrought iron is not typically used for structural works in beams. Beams are typically made from steel or concrete, which are stronger materials than wrought iron.
Option B is incorrect because wrought iron is not typically used for small sized water pipes. Water pipes are typically made from plastic or PVC, which are more corrosion-resistant materials than wrought iron.
Option D is incorrect because wrought iron is used for some of the things listed in the other options.