Which structure could be found in both male and female?

Correct option is C

The epiproct is a structure from an insect's tenth abdominal segment which not all insects possess but is present in both male and female. It is the central filament at the end of abdomen, the other two filaments are the cerci. It is much prominent in dragonflies but much reduced in damselflies.
Hence, the correct answer is Epiproct .