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.

SAM : UES :: RAT : TEZ :: LOI : ?

NSO

Explanation:

SAM : UES :: RAT : TEZ :: LOI : ?

The logic followed here is :

S → (+2) → U → (-3) → R → (+2) → T → (-8) → L → (+2) → N

A → (+4) → E → (-4) → A → (+4) → E → (+10) → O → (+4) → S

M → (+6) → S → (+1) → T → (+6) → Z → (+9) → I → (+6) → O

So, the letter-cluster that replaces the (?) to complete the series is "NSO"