Select the option that will fill in the blank and complete the given series

Select the option that will fill in the blank and complete the given series.

GHDS, KCKY, OXPC,SSWI, ?

(a)          WNDN

(b)          WMDN

(c)           WNDO

(d)          XMDN

Sol:

Pattern follows here is +4, -5, +7, +6