Computer Science Homework Help

see this doc and writing at least 500 words which one is the best way to solve SQL injection

1.Web Application Firewall  
2. Context-sensitive String Evaluation.  
3. Cloud Computing.  
4. Security Patches.
5. Homomorphic Encryption.
6. Regular Data Backups.
7. Access Control.
8. Parse Tree Evaluation.
9. Syntax Awareness Evaluation and Positive Tainting