The prophet Obadiah delivers a prophecy against Edom. What is the primary reason for God's judgment against Edom according to this prophecy?

A Edom's idolatrous practices and worship of false gods. B Edom's persistent warfare against Israel and attempts to conquer their land. C Edom's failure to assist Judah during its time of distress and taking advantage of their misfortune. D Edom's economic exploitation of neighboring nations and accumulation of wealth.