Why Monomeric saturated aliphatic carboxylic acids show carbonyl stretching frequency near 1760 cm-1, while saturated aliphatic ketones near 1720 cm-1?

• A. Mesomeric (M) effect is dominant in acids over the inductive (I) effect
• B. I effect is dominant in carboxylic acids over the mesomeric effect
• C. I effect on ketones is dominant over the M effect
• D. M effect in ketones is dominant