Select the letter-cluster that can replace the question mark (?) in the following series.
DZA, FUD, HPG, JKJ, LFM, ?

 The Given alphabet series DZA, FUD, HPG, JKJ, LFM,?

We know that alphabet position A =1, B=2, C=3, D=4 ........ Z=26 

then the given series represents in the form of alphabet position

4 26 1 , 6 21 4, 8 16 7, 10 11 10, 12 6 13 , ?

from the above representation, we can  say that  series  going on first is increasing 2 positions to next, second  is decreasing in 5 position and third is increasing 3 positions  to next 

, therefore? = 14 1 16 

? = N A P (14 1 16) Ans