Which letter set will come in place of question mark (?) in the following series?LOK, PQP, VSV, DUC, ?

Which letter set will come in place of question mark (?) in the follow

1.	Which letter set will come in place of question mark (?) in the following series?LOK, PQP, VSV, DUC, ?
A.	MTG
B.	BRE
C.	NWK
D.	LOP
Answer» D. LOP