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

RICH : IRXS :: BOOKS : ?

YLLP

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

RICH : IRXS :: BOOKS : ?

THE LOGIC FOLLOWED HERE IS :

R → (OPPOSITE ) → I

I → (OPPOSITE ) → R

C → (OPPOSITE ) → X

H → (OPPOSITE ) → S

Similarly,

B → (OPPOSITE ) → Y

O → (OPPOSITE ) → L

O → (OPPOSITE ) → L

K → (OPPOSITE ) → P

Thus, YLLP is correct.