Number of isomers for the compound dihydroxy benzene

Given data : It is given to identify  how  many isomers of the chemical dihydroxy benzene.

Explanation 

Three isomers exist: The ortho isomer of 1,2-dihydroxybenzene is known as catechol, the meta isomer of 1,3-dihydroxybenzene is known as resorcinol, and the para isomer of 1,4-dihydroxybenzene is known as hydroquinone.

Hence, the correct option ( C). 3