Select the option that is related to the fifth letter-cluster in the same way as the fourth letter-cluster related to the third letter-cluster and second letter-cluster is related to the first letter-cluster.
IGRS ∶ NJWV ∶∶ BMYF ∶ GPDI ∶∶ XQSB ∶ ?
1
BTWE
2
CTXE
3
CUXF
4
BUWF