The correct answer is option 'B' - 1 and 2.

Thermosetting materials are a type of polymer that undergoes a chemical reaction during the curing process, resulting in a cross-linked network structure. This cross-linking makes them rigid and resistant to heat, chemicals, and electrical conductivity. The processes used for thermosetting materials are compression molding and transfer molding.

1. Compression Molding:
- Compression molding is a widely used process for thermosetting materials.
- In this process, a pre-measured amount of thermosetting material in a powdered or granular form is placed into a heated mold cavity.
- The mold is then closed and pressure is applied to the material, causing it to flow and fill the mold cavity.
- The heat and pressure trigger the chemical reaction that causes the material to cross-link and harden.
- The mold is held under pressure until the material has fully cured, and then it is cooled and the part is removed from the mold.
- This process is suitable for producing large and complex parts with high dimensional accuracy.

2. Transfer Molding:
- Transfer molding is another process commonly used for thermosetting materials.
- In this process, a pre-measured amount of thermosetting material is placed into a heated chamber called a pot.
- The pot is then pressed against a mold cavity, and the material is forced into the cavity through channels called runners and gates.
- The heat and pressure cause the material to flow and fill the mold cavity, where it undergoes the chemical reaction and cures.
- Once cured, the mold is opened, and the part is removed.
- Transfer molding allows for precise control of the amount of material and pressure applied, making it suitable for producing small, intricate parts.

3. Injection Molding:
- Injection molding is not a process typically used for thermosetting materials.
- Injection molding is more commonly used for thermoplastic materials, which can be melted and solidified repeatedly.
- In injection molding, the material is heated to a liquid state and injected into a mold cavity under high pressure.
- Once cooled, the mold is opened, and the part is ejected.
- Injection molding offers high production rates and can produce complex parts with tight tolerances.
- However, it is not suitable for thermosetting materials due to their cross-linking behavior.

4. Extrusion:
- Extrusion is also not a process typically used for thermosetting materials.
- Extrusion is commonly used for thermoplastic materials to produce continuous profiles or shapes.
- In extrusion, the material is melted and forced through a die to create a specific shape.
- The material then solidifies as it cools.
- Thermosetting materials do not have the ability to melt and solidify repeatedly, so they are not suitable for extrusion.

In summary, the processes commonly used for thermosetting materials are compression molding and transfer molding. These processes take advantage of the thermosetting materials' cross-linking behavior to produce rigid and heat-resistant parts. Injection molding and extrusion, on the other hand, are more suitable for thermoplastic materials.