Option E is the most secure and robust. It utilizes environment variables to store credentials securely, includes error handling for potential query execution issues, and ensures that the cursor and connection are closed properly in a `finally' block, even if an error occurs. Option A hardcodes credentials, which is a major security risk. Options B and C don't include comprehensive error handling. Option D uses 'fetchmany(10)' , which might not fetch all results if there are exactly 10 rows and is less common for retrieving all rows.