In computers, subtraction is generally carried out by _____?

• A. 9‚Äö√Ñ√∂‚àö√ë‚àö¬•s complement
• B. 10‚Äö√Ñ√∂‚àö√ë‚àö¬•s complement
• C. 1‚Äö√Ñ√∂‚àö√ë‚àö¬•s complement
• D. 2‚Äö√Ñ√∂‚àö√ë‚àö¬•s complement