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.

NR : MI :: BK : ?

YP

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

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THE LOGIC FOLLOWED HERE IS :

N → (OPPOSITE) → M

R → (OPPOSITE) → I

SIMILARLY

B → (OPPOSITE) → Y

K → (OPPOSITE) → P