The prophecy in Obadiah focuses primarily on the downfall of which nation, highlighting their pride and mistreatment of Judah, and predicting their ultimate destruction?

A Babylon, for their destruction of Jerusalem and exile of the Israelites. B Edom, for their gloating and taking advantage of Judah's vulnerability during its distress. C Assyria, for their invasion and oppression of the Northern Kingdom of Israel. D Egypt, for their enslavement of the Israelites centuries prior.