The given letter series in below pattern.
ab a d n a
After completing the pattern, we will get complete letter series.

Correct Option: B

The given letter series in below pattern.
ab a d n a
After completing the pattern, we will get complete letter series.
ab a d n a/ a b a d na/ a badna/ a badna

As per given question, the letter series is following the below pattern.
a b c
After using the pattern the complete letter series will be as below.

Correct Option: D

As per given question, the letter series is following the below pattern.
a b c
After using the pattern the complete letter series will be as below.
a b c/ c b a/ a b c/ c b a

As per given question, the letter series is following the below pattern.
r t x y s x y z
After using the pattern the complete letter series will be as below.

Correct Option: C

As per given question, the letter series is following the below pattern.
r t x y s x y z
After using the pattern the complete letter series will be as below.
r t x y s x y z/ r t x y sx y z

The pattern of given letter series is :-
a d c
Using the same pattern, we will get complete letter series.

Correct Option: D

The pattern of given letter series is :-
a d c
Using the same pattern, we will get complete letter series.
a d c / a d c / a dc / a d c / ad c

The given letter series in below pattern.
pp q q/qp p p
After completing the pattern, we will get complete letter series.

Correct Option: A

The given letter series in below pattern.
pp q q/qp p p
After completing the pattern, we will get complete letter series.
pp q q /qp p p/ qq q p/qq p q /qq p q