The json_last_error_msg() function in PHP is used to return the error string of the ______ JSON operation.

The json_last_error_msg() function in PHP is used to return the error string of the last JSON operation. It retrieves the human-readable error message corresponding to the most recent JSON-related error. The correct option is "last." The function helps in diagnosing and troubleshooting JSON-related errors by providing descriptive error messages. For further details, refer to the PHP documentation on json_last_error_msg(): http://php.net/manual/en/function.json-last-error-msg.php