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

COOK : DQPM :: DOWN : EQXP :: ONLY : ?

PPMA

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

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

COOK : DQPM :: DOWN : EQXP :: ONLY : ?

The  logic followed here is :

C → (+1)→ D

O → (+2)→ Q

O → (+1)→ P

K → (+2)→ M

AND

D → (+1)→ E

O → (+2)→ Q

W → (+1)→ X

N → (+2)→ P

SIMILARLY

O → (+1)→ P

N → (+2)→ P

L → (+1)→ M

Y → (+2)→ A