Select the option in which the pair of letter-clusters share the same relationship as that shared by the given letter-clusters.
RS : IH

A B C D E  F G H I   J  K L M

Z Y X W V U T  S R Q P O N

RS ==> IH

Here opposite letters of the first letter cluster is forming the next letter cluster.
Option (a) TM : GN

TM ==> GN

The given logic is applicable here. So this is the correct answer.

Option (b) BX : CY

BX ==> YC

The given logic is not applicable here. So this is not the correct answer.

Option (c) RS : IT

RS ==> IH

The given logic is not applicable here. So this is not the correct answer.
Option (d) AJ : ZK

AJ ==> ZQ

The given logic is not applicable here. So this is not the correct answer.

Hence option (a) is the correct answer.