(A) 1,2-dichloroethane and 1,1- dichloroethane are positional isomers.
(B) Propanoic acid and methyl acetate are functional isomers.
(C) Methyl acetate and ethyl formate are functional isomers.
(D) o-Nitrophenol and p-nitrophenol are positional isomers.
(E) Anisole and o-cresol are functional isomers.
(F) Phenol and Cyclohexa-2,4-dien-1- one are functional isomers.