In the prophetic book of Habakkuk, what is the central theological problem Habakkuk grapples with, and what is God's surprising response to his complaint?

A Habakkuk questions why God allows the righteous to suffer while the wicked prosper, and God responds by promising immediate retribution against the wicked. B Habakkuk is concerned about the impending threat of Assyrian invasion, and God reassures him that Israel will be spared from destruction. C Habakkuk struggles with the apparent injustice of God using the more wicked Babylonians to punish Judah, and God reveals that He will ultimately judge Babylon for their wickedness. D Habakkuk doubts God's ability to fulfill His covenant promises, and God provides miraculous signs to demonstrate His power and faithfulness.