When ants bite, they inject ______.
Correct option is A. formic acid
$$\bf{Concept-}$$
When an ant bites it injects the acidic liquid into the skin. Formic acid is the common name for methanoic acid $$(HCOOH)$$.
$$\bf{Correct\ option-}$$
Option A is correct.
$$\bf{Explanation-}$$
When ants bite, they inject formic acid into the muscle tissue. This formic acid is found in the mandible of ants.