1. 

In the following question, a letter series is given. Some of the letters of the series are missing. This missing letters are given in same order as one of the four/five alternatives below the series. Find out the correct alternative.

__ml__nl__mlm__l__mlmn__

A. nnmmll
B. nmlnml
C. mnlnlm
D. nmnnnl

Answer: Option D

Explanation:

Pattern of the series as shown below

nml/mnl/nml/mnl/nml/mnl => nmnnnl

Hence, the missing letters are nmnnnl.