A series is given below. In which a letter pair is not given. Choose the correct alternative from the given ones that will complete the series.
ML, RQ, WV, BA ?

Complete the following series.
C3D, E6F, G9H, I12J, ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
Constable, Head constable, ?, Inspector

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
c_e_cd_f_d_f

DIRECTIONS: In the following question, find the missing letters in the given series.
AOP, CQR, EST, GUV, ? 

In each of the letter series, find the missing letters.

a – c c a b c – a b – c – b c c 

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
AY, CW, EU, ?

Which of the following letter-clusters will replace the question mark (?) in the given series?
 PK, GT, XC, OL, ?