Final answer:
Carboxylic acids react with alcohols to form esters, known as an esterification reaction, and sulfuric acid can catalyze this reaction, but it's not a reactant. Nitric acid oxidizes alcohols and does not typically form esters with them. Therefore, the answer is b. carboxylic acid.
Step-by-step explanation:
Among the given options, carboxylic acids can react with alcohols to form esters. This process is known as esterification. In this reaction, the -OH group of the carboxylic acid (e.g., acetic acid) reacts with the -OH group of the alcohol (e.g., ethanol) to produce an ester (e.g., ethyl acetate) and water. While sulfuric acid is not typically a reactant in esterification, it often serves as an acid catalyst to speed up the reaction between a carboxylic acid and an alcohol.
It's also worth noting that strong oxidizing agents like nitric acid often oxidize alcohols to form different products like saccharic acids, rather than participating in esterification. Therefore, the correct answer is b. carboxylic acid.