SSC CHSL 5 Mar 2018 Shift 1 Paper

Series : HPA, FMZ, DJY, BGX, ?
The pattern followed in each letter of the terms is :
1st letter : H (-2 letters) = F (-2 letters) = D (-2 letters) = B (-2 letters) = Z
2nd letter : P (-3 letters) = M (-3 letters) = J (-3 letters) = G (-3 letters) = D
3rd letter : A (-1 letter) = Z (-1 letter) = Y (-1 letter) = X (-1 letter) = W
Thus, missing term = ZDW