Even for the citizens of the East Bloc's most prosperous nation, the lure of capitalism is irresistible.

Answer: Option C

Prosperous : successful in material terms; flourishing financially.
Exploited : make full use of and derive benefit from (a resource).
Under-developed : not fully developed.
Impoverished : deprived of strength or vitality.
Destitute : extremely poor and lacking the means to provide for oneself.

Antonym of Prosperous is Impoverished