Select the combination of letters that when sequentially placed in the gaps of the given letter series will complete the series.
_U_GU_UN_UK_NGU
1
GNKUU
2
UUNKG
3
NKUUG
4
KNKGU
Select the combination of letters that when sequentially placed in the gaps of the given letter series will complete the series.
_U_GU_UN_UK_NGU