Final answer:
An enumerated type is a class that defines a set of named constants, improving code readability and error prevention by restricting variable values to a predefined set.
Step-by-step explanation:
An enumerated type, or enum, is c) A class in programming that consists of a set of named constants called enumerators. Enums are used in programming languages such as C, C++, C#, and Java to create a type that can only take one of a finite number of values. This helps make the code more readable and maintainable by grouping related constants together and ensuring variable values are restricted to the predefined set.
For example, in a program with a variable representing the days of the week, rather than using integers (where errors like using '8' for a day could occur), one could use an enum with values like MONDAY, TUESDAY, etc., which restricts the variable to using one of those specified days and thus minimizes potential errors.