ans given: b
@samanta_isika Positional Isomers are the Constitutional Isomers which have the same carbon skeleton and the same functional groups but differ from each other in the position of the functional groups
In chain isomerism, or skeletal isomerism, components of the (usually carbon) skeleton are distinctly re-ordered to create different structures.
Metamers are compounds having the same molecular formula but different number of carbon atoms (alkyl groups) on either side of functional group (i.e., -O-,-S-, -NH-, -C(=O)-) and the phenomenon is called metamerism.
Hence the given compounds are metamers which is none of these