The correct answer is A. Formic acid.
Formic acid is a colorless, pungent liquid that is found in the venom of ants. It is the simplest carboxylic acid and is used in a variety of industrial and commercial applications. Formic acid is also found in nature, in some plants and animals.
Malic acid is a white, crystalline solid that is found in many fruits, such as apples and pears. It is also used as a food additive and in the production of some pharmaceuticals.
Perchloric acid is a strong, corrosive acid that is used in a variety of industrial applications. It is also used in the production of some explosives.
Nitric acid is a strong, corrosive acid that is used in a variety of industrial applications. It is also used in the production of some explosives and fertilizers.
Formic acid is the only acid listed that is found in ant bites.