Final answer:
Without the actual SQL statements or table details, it is impossible to specify which SQL statement will return an error. Common SQL errors stem from syntax issues, nonexistent references, and data type mismatches.
Step-by-step explanation:
A SQL statement will return an error message if it contains syntax errors, references to nonexistent columns or tables, or violates any data integrity constraints. Without the actual SQL statements or the structure and data of the CUSTOMERS table, it is not possible to determine which specific SQL statement would return an error message. In a general context, common mistakes that lead to SQL errors include misspelling keywords or table/column names, incorrect data types in WHERE clause comparisons, and syntactical errors like missing commas or unclosed quotations.