Which of the following is not a third generation language?

Assembly language is not a third-generation language.
First-generation languages are machine languages, which directly correspond to the instructions understood by a computer's hardware. It is difficult for humans to understand and use machine language directly.
Second-generation languages, such as assembly languages, use symbolic representations of the machine instructions. They are more readable and easier to use than machine languages. Assembly language instructions are specific to a particular computer architecture and closely related to the computer's hardware.
Third-generation languages are higher-level programming languages designed to be more programmer-friendly. They are further away from the computer's hardware and closer to human language. These languages are designed to be independent of any specific computer architecture. Examples of third-generation languages include FORTRAN, COBOL, and Basic.
Therefore, assembly language is not a third-generation language, as it is a second-generation language.