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

PURPOSE : QWUTTYL :: SERVICE : ?

TGUZNIL

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

**********************************************************

THE LOGIC FOLLOWED HERE IS :

PURPOSE : QWUTTYL :: SERVICE : ?

P → (+1) → Q

U → (+2) → W

R → (+3) → U

P → (+4) → T

O → (+5) → T

S → (+6) → Y

E → (+7) → L

Similarly,

S → (+1) → T

E → (+2) → G

R → (+3) → U

V → (+4) → Z

I → (+5) → N

C → (+6) → I

E → (+7) → L

Thus, TGUZNIL is correct.