Bakelite is an example of

thermosetting

The answer is 4. thermosetting.

Bakelite is a thermosetting polymer. Thermosetting polymers are polymers that cannot be remelted or reshaped once they have been cured. They are formed by a cross-linking reaction between the monomers, which creates a strong, rigid network. Bakelite is a good example of a thermosetting polymer because it is hard, durable, and heat-resistant. It is often used in applications where a strong, non-deformable material is needed, such as electrical insulation, kitchenware, and jewelry.

Elastomers are polymers that can be stretched to a large extent without breaking. They are often used in applications where flexibility is important, such as tires and rubber bands. Fibres are long, thin strands of material that are used to make textiles, ropes, and other products. Thermoplastics are polymers that can be melted and reshaped repeatedly. They are often used in applications where a lightweight, moldable material is needed, such as plastic bottles and food containers.

So, the answer to the question is 4. thermosetting. Bakelite is a thermosetting polymer, not an elastomer, fibre, or thermoplastic.