What is a Symbol in JavaScript?

A Symbol in JavaScript is defined as a unique and immutable primitive value primarily used to create unique identifiers for object properties. This uniqueness means that even if two Symbols are created with the same description, they will not be equal to each other. Symbols provide a way to avoid name clashes between object properties when extending existing objects or libraries, making them particularly useful in scenarios where you want to add properties without risking pollution of the object’s namespace.

In contrast to other data types, Symbols help prevent accidental overriding of properties, as their uniqueness guarantees that each Symbol property remains distinct. This makes them a powerful tool for defining private properties or methods in an object-oriented programming context, as these Symbol-keyed properties won't interfere with other properties that may share the same name in the broader scope.

The other options do not accurately describe a Symbol. For instance, while the first option mentions a type of variable that can hold multiple values, Symbols are singular and unique. The third option incorrectly identifies Symbols as methods for random number generation which is unrelated to their function. Finally, referring to a Symbol as merely an object property type oversimplifies its characteristics and overlooks its fundamental role as a primitive value.