Select the combination of letters that when sequentially placed in the blanks of the given letter series will complete the series. e_geef_gg_ee_f_ggg

f, f, e, f, f f, f, f, f, f g, f, e, f, f f, g, f, g, g

f, f, e, f, f

e f g / e e f f g g / e e e f f f g g g f , f , e , f , f