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.

KFUB : BKLG :: PNTD : GSKI :: IVFQ : ?

Given: KFUB : BKLG :: PNTD : GSKI :: IVFQ : ?

Logic: first letter decreasing by 9, second letter increasing by 5, third letter decreasing by 9 and fourth letter increasing by 5.

As,

K-9=B, F+5=K, U-9=L, B+5=G

And

P-9=G, N+5=S, T-9=K, D+5=I

Similarly,

I-9=Z, V+5=A, F-9=W, Q+5=V

So, ZAWV is the required code.

Thus, correct option is (a).