Enantiomers.
here configuration of each carbon will be opposed.
to find out relationship, assign R/S configuration and compaird it.
if it is RR|SS then Enantiomer
RR|RS then diaste...
Option A enantiomers
Assign R and S configuration if it comes R,R on first isomers and S,S on second isomer and vice versa.... Or R,S or S,R in first isomer and S,R or R,S on seco...