Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.
KST, OWX, SAB, WEF, ?
1
BIH
2
AIJ
3
BIK
4
AJK
Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.
KST, OWX, SAB, WEF, ?