Which of the following statements is true about thermosetting polymers?

Thermosetting polymers are a type of polymer that, once they have been cured or hardened, cannot be remelted or reshaped. This property is due to the cross-linking of the polymer chains during the curing process, which gives them a strong and rigid structure. As a result, they maintain their shape and strength even when subjected to heat. This characteristic makes them ideal for applications that require materials to withstand high temperatures without deforming or losing their structural integrity, such as in electrical insulators, kitchenware, and automotive parts.

The other options do not describe the nature of thermosetting polymers accurately. Unlike thermoplastic polymers, which can be reheated and reshaped, thermosetting polymers do not possess this capability. They are also generally not known for flexibility or stretchiness; instead, they are often quite rigid. Additionally, thermosetting polymers typically do not dissolve easily in solvents due to their tightly cross-linked structure, further reinforcing their durability and stability under a variety of conditions.