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 _ cdaab _ cc _ daa _ bbb _ ccddd

A. bdbda
B. bddca
C. dbbca
D. bbdac

Answer: Option D

Explanation:

The series is abca / aabbccdd / aaabbbcccddd.

Thus, each letter of first sequence is repeated two times in the second sequence and three times in the third sequence.