Select the option that is related to the fifth alphanumeric-cluster in the same way as the second alphanumeric-cluster is related to the first alphanumeric-cluster and the fourth alphanumeric-cluster is related to the third alphanumeric-cluster.

WXY72 : ZAB29 :: CDE12 : FGH21 :: IJK30 : ?

LMN39

WXY72 : ZAB29

W(23) + 3 = 26(Z) , X(24) + 3 = 1(A) , Y(25) + 3 = B

W + X + Y = 23 + 24 + 25 = 72 

Z + A + B = 26 + 1 + 2 = 29

CDE12 : FGH21

C(3) + 3 = 6(F) , D(4) + 3 = 7(G) , E(5) + 3 = 8(H)

C + D + E = 3 + 4 + 5 = 12

F + G + H = 6 + 7 + 8 = 21

Similarly ,

IJK30 : ?

I(9) + 3 = 12(L) , J(10) + 3 = 13(M) , K(11) + 3 = 14(N)

I + J + K = 9 + 10 + 11 = 30

L + M + N = 12 + 13 + 14 = 39

i.e. LMN39 is correct answer