Select the option in which the letters share the same relationship as that shared by the given pair of letters.
RP : SQ :: ?

Given letter pair in the question is immediately succeeding the next letter pair.

RP : SQ ==> R+1 P+1 ==> SQ

Option (a) JL : IK

JL ==> J+1 L+1 ==> KM

This option is not following the given logic.

Option (b) RV : QW

RV ==> R+1 V+1 ==> SW

This option is not following the given logic.

Option (c) MA : NZ

MA ==> M+1 A+1 ==> NB

This option is not following the given logic.

Option (d) KG : LH

KG ==> K+1 G+1 ==> LH

This option is following the given logic. Hence it will be the answer.