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 : a _ abbb _ ccccd _ ddccc _ bb _ ba

A. abcda
B. abdbc
C. abdcb
D. abcad

Answer: Option C

Explanation:

The series is aaa / bbbb / cccc / dddd / cccc / bbbb / a.