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

I4D : G9F :: L16S : J25U :: W64R : ?

U81T

1   2    3    4   5    6   7     8    9  10  11  12  13

 A   B   C    D   E    F   G    H    I    J    K    L   M

 ↓    ↓    ↓    ↓    ↓     ↓   ↓    ↓     ↓   ↓    ↓    ↓    ↓

 Z   Y    X   W   V    U   T    S    R   Q   P    O   N

26  25  24  23  22  21  20  19  18  17  16  15  14

I4D : G9F :: L16S : J25U :: W64R : ?

THE LOGIC FOLLOWED HERE IS;

I4G : G9F,

I -> (-2) -> G

4 -> (2+1) ->\( {3 }^{ 2} \)  = 9

G -> (+2) -> F

And,

L -> (-2) -> J

16 -> (1+4) ->\( {5 }^{ 2} \)  = 25

S -> (+2) -> U

Similarly,

W -> (-2) -> U

64 -> (1+8) ->\( {9 }^{ 2} \)  = 81

R -> (+2) -> T

Thus, U81T is correct.