In the given letter-cluster pairs, the first Letter-cluster is related to the second letter cluster following a certain logic. Study the given pairs carefully. and from the given options. select the pair that follows the same logic.
ADG : EHK
TJF : XNJ

ADG : EHK​
TJF : XNJ

Logic: Each letter is increasing by +4 letter forward in alphabetical order

ADG : EHK

A + 4 = E, D + 4 = H, G + 4 = K

​TJF : XNJ

T + 4 = X, J + 4 = N, F + 4 = J

Let's check all the options;

Option (a); KOH : OSL

K + 4 = O, O + 4 = S, H + 4 = L (Follow) 

Option (b); JQR : NTV

J + 4 = N, Q + 4 = U,R + 4 = V (Not follow)

Option (c); FJW : HLZ

F + 2 = H, J + 2 = L, W + 3 = Z, (Not follow)

Option (d); IPD : RKW

I + 9 = R, P - 5 = K, D + 19 = W, (Not follow)

Thus, the correct answer is (a) KOH : OSL .

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