The correct answer is D. All of these.
Urea resin, phenolic resin, and resorcinol resin are all synthetic resins. They are all made by reacting a phenol with an aldehyde. The resulting resins are then used in a variety of applications, including adhesives, coatings, and laminates.
Urea resins are the most common type of synthetic resin. They are relatively inexpensive and easy to produce. Urea resins are used in a variety of applications, including adhesives, coatings, and laminates.
Phenolic resins are more expensive than urea resins, but they are also more durable. Phenolic resins are used in a variety of applications, including electrical insulation, brake pads, and gears.
Resorcinol resins are the most expensive type of synthetic resin, but they are also the most durable. Resorcinol resins are used in a variety of applications, including aircraft parts, boat hulls, and bowling balls.