Answer : 2. "Backup"
Explanation :

The best way to protect your hard drive data is a multi-tiered approach that includes the following:-

1. Data Backup: This is the most important security measure. If your hard drive fails, is stolen, or the data becomes corrupted, you must have a way to restore the data. Data backups should be maintained regularly and in a safe location.

2. Password Protection: Password protects your hard drive. This will help prevent unauthorized access. Use strong passwords that are easy to remember, but difficult to guess.

3. Encryption: Encrypt your hard drive. This will make the data unreadable to people who do not know the password. Encryption provides an additional security layer that keeps data safe in the event of theft or loss.

4. Virus and malware protection: Install a reliable antivirus and antimalware program on your computer. This will help protect your data from harmful software.

5. Secure file sharing: If you plan to share your data with others, make sure you do so in a secure manner. Use a secure file-sharing service that offers encryption and password protection.