In this type of questions, a series of single, pairs or groups of letters or combinations of letters and numerals are given. The terms of the series form a certain pattern as regards the position of the letter in the English alphabet. Find the missing or wrong term in series 

1)

Z, Y,  X, U, T, S, P, O, N, K, ?, ?


A) H, G

B) H, I

C) I, H

D) J, I

Answer:

Option D

Explanation:

$\left(Z\rightarrow Y\rightarrow X\right) - 3 \rightarrow $

$\left(U\rightarrow T\rightarrow S\right) - 3 \rightarrow$

$\left(P \rightarrow O\rightarrow N\right) - 3 \rightarrow$

$\left(K\rightarrow J\rightarrow I\right)$

Hence the answer is (d).