1.  In alphabet series, some alphabets are missing which are given in that order as one of the alternatives below it. Choose the correct alternative : abb _ baa _ a _ bab _ aba

A. abba
B. abab
C. ccac
D. aabb

Answer: Option A

Explanation:

The series is abba / baab / abba / baab / a.

Thus, the pattern abba, baab is repeated.