In the following question, select the related letter pair from the given alternatives.
RPD: WUI :: ?

Correct option is C

Given: RPD: WUI :: ?
We know the logic follows +5 for each corresponding letter in the pair. Let's break down the relationship for RPD to WUI:
R(18)+5=W(23)
P(16)+5=U(21)
D(4)+5=I(9)
Now, let's apply the same +5 logic to the given options to find the matching pair:
Option (a) BAC : OTT
B → O: B(2)+13≠O(15)
This option does not follow the +5 logic.
Option (b) LDK : CFK
L → C: L(12)−9≠C(3)
This option does not follow the +5 logic.
Option (c) XYM : CDR
X(24)+5=C(3)
(25)+5=D(4)
M(13)+5=R(18)
This follows the +5 logic correctly.
Option (d) XOL : UPL
X → U: X(24)−3≠U(21)
This option does not follow the +5 logic.
Thus, the correct answer is (c).