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

Which is the next term in the following sequence of letter clusters?
PLaN, OJbP, NHcR, MFdT, LDeV,

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

a – c c a b c – a b – c – b c c 

Choose the correct alternative from the given ones that will complete the given sequence.
ALN, DNP, GPR, ?

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

Choose the correct alternative from the given ones that will complete the given sequence.
LXF, MTJ, NPN, OLR, ?

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

If it is possible to make a meaningful word of English together with the first, fifth and eighth letters of the word APTITUDES, how many total words can be made of this type?