What is a syntax error?

A syntax error occurs when the code violates the grammar rules of the programming language. This means that the code written by the programmer does not conform to the expected structure or format that the programming language specifies. Each programming language has its own rules and conventions, and when these are broken—such as missing punctuation, using keywords incorrectly, or improper use of brackets—the code cannot be compiled or interpreted correctly, leading to a syntax error.

This type of error typically arises during the parsing stage, where the compiler or interpreter checks the source code for its syntactical correctness before executing it. It is essential for programmers to write correct syntax to ensure that their code can be processed by the compiler, otherwise the program won't compile or run as intended. The other options do not accurately define a syntax error, as they reference issues related to performance, variable naming conventions, or runtime behavior, which are distinct from syntax errors.