How is negative of an image obtained with intensity levels [0,L-1] with “r” and “s” being pixel values?

• A. s = L ‚Äö√Ñ√∂‚àö√ë‚àö¬® 1 + r
• B. s = L ‚Äö√Ñ√∂‚àö√ë‚àö¬® 1 ‚Äö√Ñ√∂‚àö√ë‚àö¬® r
• C. s = L + 1 + r
• D. s = L + 1 + r