Select the related word/letters/number from the given alternatives.ABCD : HYXE :: MNOP : ?

Let's find the logic connecting the first pair:$\text{A}\stackrel{+7}{\to }\text{H}$$\text{B}\stackrel{+23\text{ or }-3}{\to }\text{Y}$$\text{C}\stackrel{+21\text{ or }-5}{\to }\text{X}$$\text{D}\stackrel{+1}{\to }\text{E}$ Alternatively, checking opposite pairs or a specific shifting pattern:Let's look at the position values:$\text{A}=1,\text{B}=2,\text{C}=3,\text{D}=4$$\text{H}=8,\text{Y}=25,\text{X}=24,\text{E}=5$ Notice that:$1+7=8\to \text{H}$$2+23=25\to \text{Y}$ (or $-3$)$3+21=24\to \text{X}$ (or $-5$)$4+1=5\to \text{E}$ Let's apply the same shifts to $\text{MNOP}$ ($\text{M}=13,\text{N}=14,\text{O}=15,\text{P}=16$):$13+7=20\to \text{T}$$14-3=11\to \text{K}$$15-5=10\to \text{J}$$16+1=17\to \text{Q}$ Thus, the code is $\text{TKJQ}$.