What is a short chain of monomers whose chain growth has been halted?

The correct choice is 'oligomer' because it specifically refers to a short chain of monomers that has not fully polymerized or formed a long chain. Oligomers consist of a limited number of repeating units, typically between two and ten, and the term highlights the fact that the polymerization process has been stopped or is incomplete.

This is important in various applications, such as in the cosmetic and nail industries, where oligomers can be used to create products with specific properties that differ from fully polymerized compounds. They can also possess unique characteristics that make them useful for certain formulations.

Other terms do not represent this concept accurately. For example, a polymer is a longer chain of monomers that has undergone complete polymerization, a catalyst is a substance that speeds up a chemical reaction but is not a product itself, and acrylic describes a specific type of polymer or material rather than the short chain of unreacted monomers. Understanding the distinction helps clarify the nature and properties of different chemical structures used in nail products and procedures.