The correct option is A 1 and 2
Metamerism :
Structural isomers in which there is a difference in the relative position of alkyl group around polyvalent atom/functional groups.
In options (1) and (2) the relative position of alkyl groups around the functional group can be different. So, they show metamerism. thus Diethyl thioether(C2H5−S−C2H5) and Methyl propyl thioether (CH3−S−C3H7) are metamers.