What are 1NF, 2NF, and 3NF and why are they used?

• A. 1NF eliminates repeating groups; 2NF eliminates partial dependencies on candidate keys; 3NF eliminates transitive dependencies.
• B. 3NF eliminates all dependencies.
• C. 1NF focuses on indexing.
• D. They are for performance optimization.

Answer: (A)