Which of the following is a preprocessor directive in C?

Explanation

The correct answer is (a) #include. #include is a preprocessor directive in C. Preprocessor directives are instructions that are processed by the compiler before the actual compilation process. The #include directive is used to include header files in your C program. Header files contain function declarations, variable declarations, and other definitions that your program needs from external libraries or from other source files.In conclusion, #include is a preprocessor directive that allows you to incorporate header files into your C program, enhancing code modularity and reusability. The other options are keywords used for different purposes within the C programming language.