India is still a virgin land exploring its tourism potential.

Answer: Option D

Undone : not tied or fastened.
Unexplored : (of a country or area) not investigated or mapped.
Uncouth : lacking good manners, refinement, or grace.
Unexploited : (of resources) not used to maximum benefit.
Virgin : not yet used, exploited, or processed.

Synonym of Virgin is Unexploited