Correct Answer: MSOEWAD

Solution : Given:
AESO_WDAE_ _MWDA_SOM_D_ESOMW_

To fill the series we have to divide the series – AESO_WD / AE_ _MWD / A_SOM_D / _ESOMW_
Let's check each option –
First option: MOSEDAW ; AESO M WD / AE OS MWD / A E SOM D D / A ESOMW W (No repeated pattern has been found.)
Second option: MSOEDAW ; A ESO M WD / AE SO MWD / A E SOM D D / A ESOMW W (No repeated pattern has been found.)
Third option: MOESWAD ; A ESO M WD / AE OE MWD / A S SOM W D / A ESOMW D (No repeated pattern has been found.)
Fourth option: MSOEWAD ; A ESO M WD / AE SO MWD / A E SOM W D / A ESOMW D (AESOMWD is repeated in the series.)

So, the series becomes – AESOMWDAESOMWDAESOMWDAESOMWD. Hence, the fourth option is correct.