In esterification, hydroxide ion for making water comes from
A. Acids
B. Alcohols
C. Ketone
D. Carbohydrate

Hint: Esterification is the reaction of carboxylic acids and alcohols in the presence of an acid catalyst like concentrated sulfuric acid or dry hydrochloric acid resulting in the formation of esters. Esters possess an aromatic sweet smell.

Complete Step by Step Solution:
Carboxylic acids and alcohols react to form esters.
This reaction happens in the catalyst by an acid like concentrated sulfuric acid or dry hydrochloric gas etc.
The fulfilment of the reaction is depicted by the evolution of sweet or fruity-smelling esters.
This reaction is called the esterification reaction.
The mechanism of the reaction is as follows:

Image: Esterification mechanism
The first step involves the protonation of carboxylic acid.
The second step involves the attack of the lone pair present on ethyl alcohol on the carbonyl carbon of acetic acid.
The third step involves the losing water molecule from the resulting product.
The fourth step involves the loss of proton giving rise to the ester.
From the mechanism, we can see that the hydroxide ion comes from carboxylic acids.

So, option A is correct.

Additional Information: An ester possesses a nice odour. They are utilised in the scent and food items business. These are organic compounds we receive in fats and oils.

Note: Esters are formed from the treatment of carboxylic acids with alcohols. Esters are aromatic compounds and thus are highly effective in scents, makeup products, and food flavors. They are effective as an organic solvent also. They are effective in the generation of soaps and detergents.