Direction: Which one set of letters when sequentially placed at the gaps in the given letter series shall complete it.
- 
					 __ ab__a__bba__bb_a_b
- 
                        - abbbab
- babbba
- bbaabb
- abaaab
 
Correct Option: D
The pattern of given letter series is :-
a a b b
Using the same pattern, we will get complete letter series.
a a b b /a a b b/a a b b/ a a b b
 
	