Polyester reinsin polyurethane reins in is:

Explanation

Polyester and polyurethane resins are commonly used as multipart adhesives, meaning they require mixing two or more components before application. This characteristic allows them to form strong, durable bonds suitable for various industrial applications. On the other hand, hot adhesives are thermoplastic and applied in a molten state, which is not typical for polyester or polyurethane resins. One-part adhesives are ready-to-use formulations that do not require mixing, and contact adhesives involve a different application process where the adhesive is applied to both surfaces and allowed to dry before joining. These characteristics do not align with the nature of polyester and polyurethane resins, making 'Multipart adhesive' the correct answer.