Correct option is C
In the C programming language, an identifier is the name used for variables, functions, arrays, etc. To be valid, an identifier must follow these rules:
Rules for Valid Identifiers in C:
Must begin with a letter (A–Z or a–z) or an underscore (_).
Cannot start with a digit (0–9).
Can contain letters, digits, and underscores but no special characters (e.g., -, $, %).
Cannot be a reserved keyword in C.
