The correct answer is D. All of these.
Condensation polymerization is a type of polymerization that occurs when two or more monomers react with each
other to form a polymer, with the elimination of a small molecule such as water or alcohol. Phenol formaldehyde, carbamide, and melamine-formaldehyde are all examples of condensation polymers.Phenol formaldehyde is a thermosetting resin that is used in a variety of applications, including adhesives, coatings, and laminates. It is formed by the reaction of phenol and formaldehyde, which eliminates water to form a cross-linked polymer.
Carbamide is a white, crystalline solid that is used in a variety of applications, including fertilizers, explosives, and plastics. It is formed by the reaction of ammonia and carbon dioxide.
Melamine-formaldehyde is a thermosetting resin that is used in a variety of applications, including dinnerware, countertops, and laminates. It is formed by the reaction of melamine and formaldehyde, which eliminates water to form a cross-linked polymer.
In conclusion, all of the options are correct. Phenol formaldehyde, carbamide, and melamine-formaldehyde are all examples of condensation polymers.