What is an identifier in programming?

An identifier in programming refers to a name used to identify a variable, function, class, module, or other user-defined item. Identifiers are essential as they differentiate one element from another in code, allowing the programmer to reference stored data or functionalities throughout the program. This naming convention enables better readability and maintainability of code by providing meaningful identifiers that convey the purpose of the variable or function.

For instance, if a programmer defines a variable to hold the age of a student, naming it "studentAge" makes it clear what the variable holds, whereas a generic name like "var1" would not convey any specific information. Identifiers can include letters, digits, and underscore characters, but they must begin with a letter or an underscore.

The other options provided do not accurately capture the essence of identifiers. For instance, while a symbol representing a value refers to literals in programming, it does not apply to identifiers. A specific memory address relates more to how data is stored in the computer's memory, while keywords are reserved words in a programming language that have special meanings and cannot be used as identifiers.