Correct Answer: EISIEUD

Solution : Given:
FIR_DF_ _EDF_T_DFI_E_

To fill the series, we have to divide the series – FIR_D / F_ _ED / F_T_D / FI_E_
Let's check each option –
First option: EISIEUD; FIRED / FISED / FITED / FIUED (FIED is repeated in the series and the third letter of each part are in sequential alphabetical order.)
Second option: EGSJEUE; FIRED / FGSED / FJTED / FIUEE (No repeated pattern has been found.)
Third option: EHSIEUD; FIRED / FHSED / FITED / FIUED (No repeated pattern has been found.)
Fourth option: EISIEUE; FIRED / FISED / FITED / FIUEE (No repeated pattern has been found.)

So, the series becomes→FIREDFISEDFITEDFIUED. Hence, the first option is correct.