Which one set of letters when sequentially placed at the gaps in the given letter series shall complete it ?

_ bc _ ca _ aba _ c _ ca

A. abcbb

B. bbbcc

C. baaba

D. abbcc

Answer: Option A

Solution(By Examveda Team)

The series is,
abc b ca c aba b c b ca.
The letters are changing their place in a cycling order.