Select the combination of letters that when sequentially placed in the gaps of the given letter series will complete the series. ug_ _s_de_gt_ _gd_u_ _ _sgde

tghuhesgth thguhsegth tghuhesght thgushegth

thguhsegth

After dividing the series into three groups of 8 each and comparing the corresponding term. Repetitive unit is found to be ugthsgde. The series is: ugthsgde / ugthsgde / ugthsgde So, the code will be thguhsegth