Which on set of letter complete the given series ?
_bc_ca_aba_c_ca

Complete the following alphabet series.
ZA : YB :: YC :?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
K6V, M12U, O18T,?

Fill in the blank by suitable letters.
a_c_ba_ca_cb

Complete the following alphabet series.
ABC, PQR, DEF, STU, ?

Directions : In each of the following letter series, some of the letters are missing which are given in that order as one of the alternatives below it.

ab ---b -bbaa- 

Arrange the given words in the sequence in which they occur in the dictionary.
1. Energy
2. Earlobe
3. Economics
4. Edition
5. Editor

A series is given with one term  missing. Choose the correct alternative from the given ones that will complete that series.
DJ , EM , FP, ?