a) Lamination
b) Plating
c) Co-extrusion
d) Calendering

Answer: c
Explanation: Co-extrusion is a process which combines layers of two or more plastics together at the point of extrusion. Lamination is the process of packaging via combination of two or more materials by a solvent, adhesive or heat. Calendering is a complementary process to film and sheet extrusion, which involves the formation of continuous sheets of controlled thickness by passing plastic materials through rollers. Plating is the process of coating any surface (especially metal) by other metal, mostly by electrochemical cell.