Which units are generally part of the lexical structure of programming languages?

The correct choice highlights components that are fundamental to the lexical structure of programming languages. Identifiers, keywords, and literals all play crucial roles in how programs are written and understood by compilers and interpreters.

Identifiers are names given to elements such as variables, functions, and objects. They allow programmers to refer to these elements within the code. Keywords, on the other hand, are reserved words defined by the programming language that have special meanings and functionalities, such as control flow or data definition. Finally, literals represent fixed values written directly in the code, such as numbers or strings, which the language interprets as constant expressions.

Collectively, these units form the basic building blocks of the lexical structure, facilitating the syntax and grammar of program writing. The other choices contain components that are more advanced and related to the structure and organization of code rather than its foundational lexical elements. Functions, algorithms, and conditions deal with higher-order concepts of programming logic, while data types, arrays, loops, modules, classes, and interfaces pertain to organization and functionality, rather than the lexical fundamentals.