Select the related word/letters/number from the given alternatives.IKMO : PRTV :: RTVX : ?

Let's look at the positional values of the letters:$\text{I}=9,\text{K}=11,\text{M}=13,\text{O}=15$$\text{P}=16,\text{R}=18,\text{T}=20,\text{V}=22$ The pattern of shift between $\text{IKMO}$ and $\text{PRTV}$ is:$9+7=16\to \text{P}$$11+7=18\to \text{R}$$13+7=20\to \text{T}$$15+7=22\to \text{V}$ Applying the same $+7$ logic to $\text{RTVX}$ ($\text{R}=18,\text{T}=20,\text{V}=22,\text{X}=24$):$18+7=25\to \text{Y}$$20+7=27\to 27-26=1\to \text{A}$$22+7=29\to 29-26=3\to \text{C}$$24+7=31\to 31-26=5\to \text{E}$ The resulting string is $\text{YACE}$.