In the food and beverage industry, the use of preservatives and fungicides is common, and sodium benzoate is the most common substance. Observe the structure of sodium benzoate below. Identify among the alternatives the one that correctly indicates the organic function of this compound.

The text presents a molecule and asks for the identification of its organic function.
a. Carboxylic acid.
b. Carboxylic acid salt.
c. Acyl halide.
d. Ketone.
e. Alcohol.