SSC CHSL 7 Mar 2018 Shift 3 Paper

Series : PCK, RFM, TJO, VOQ, ?
The pattern followed in each letter of the terms is :
1st letter : P (+2 letters) = R (+2 letters) = T (+2 letters) = V (+2 letters) = X
2nd letter : C (+3 letters) = F (+4 letters) = J (+5 letters) = O (+6 letters) = U
3rd letter : K (+2 letters) = M (+2 letters) = O (+2 letters) = Q (+2 letters) = S
Thus, missing term = XUS