What are the two register sets used in Z80?

• A. C‚Äö√Ñ√∂‚àö√ë‚àö¬•D‚Äö√Ñ√∂‚àö√ë‚àö¬• and BC‚Äö√Ñ√∂‚àö√ë‚àö¬•
• B. CD and BD
• C. IV and MR
• D. Main and alternate