What do the syntax rules specify in programming?

The syntax rules in programming define which statements or instructions are considered legal within the programming language. These rules dictate the structure and composition of valid code, including the correct placement of keywords, operators, and punctuation necessary for the program to be understood by the compiler or interpreter. If a programmer writes code that does not adhere to these syntax rules, the code will not compile or run, resulting in errors.

Understanding syntax is crucial for effective programming as it ensures that the intended commands are correctly structured. This allows the code to execute as expected, enabling developers to create functional software applications. The other options touch on specific aspects of programming (such as compiling, writing comments, or defining variables), but they do not encompass the broader role of syntax rules in defining the legality of statements in code.