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.

ACT : KCD :: EAR : OAB :: EYE : ?

OYO

Pattern followed is :

ACT : KCD

A(1) + 10 =(11)K , C = C (same) , T(20) - 16 = (4)D

EAR : OAB

E(5) + 10 =(15)O , A = A (same) , R(18)- 16 = (2)B

Similarly ,

EYE : ?

E(5) + 10 =(15)O , Y = Y (same) , E(5) + 10 =(15)O

OYO , is correct answer .