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.

__zy__zxy__yxzx__zyx__xy
A. yxzyz
B. zxyzy
C. yzxyx
D. xyzzy

Answer: Option A

Explanation:

Pattern of the series as shown below

yzy/xzx/yzy/xzx/yzy/xzx/y => yxzyz.

The sequence is made of repetition of patterns 'yzy' and 'xzx' alternatively.

Hence, the missing letters are yxzyz.