The correct option is C. Malachi. Detailed Explanation:

1. Understanding the Context: The question asks about a prophet who spoke extensively about the restoration of Israel and the coming of the Messiah. This is a significant theme in the prophetic literature of the Old Testament, where various prophets addressed the future hope of Israel, including the promise of a Messiah.
2. Who is Malachi?: Malachi is the last book of the Old Testament and is often considered a post-exilic prophet. His prophecies were directed towards the people of Israel after their return from Babylonian exile. Malachi's messages include themes of judgment, the need for repentance, and the promise of a coming messenger who would prepare the way for the Lord (Malachi 3:1). This messenger is often interpreted as a reference to John the Baptist, who would herald the coming of Jesus Christ, the Messiah.
3. Key Themes in Malachi:
4. Restoration of Israel: Malachi emphasizes the need for the people to return to God and the restoration of their covenant relationship with Him. He calls for genuine worship and faithfulness.
5. The Coming of the Messiah: Malachi prophesies about the coming of the Lord, which is interpreted as a messianic prophecy. This is significant because it connects the Old Testament prophecies to the New Testament fulfillment in Jesus Christ.

Why the Other Options are Incorrect:

• A. Zephaniah: Zephaniah prophesied during the reign of King Josiah and focused on the coming judgment against Judah and the nations. While he does speak about restoration, his primary emphasis is on judgment and the Day of the Lord rather than the coming of the Messiah.
• B. Micah: Micah is known for his prophecies about social justice and the coming ruler from Bethlehem (Micah 5:2). While he does mention the future hope of Israel, his focus is more on social issues and the nature of true worship rather than an extensive discussion on the Messiah.
• D. Obadiah: Obadiah's prophecy is primarily about the judgment against Edom for its actions against Israel. His message is brief and does not focus on the restoration of Israel or the coming of the Messiah in the same way that Malachi does.

Summary of Key Points:

• Malachi is the prophet who extensively discusses the restoration of Israel and the coming of the Messiah.
• His prophecies emphasize the need for repentance and genuine worship.
• Malachi foretells the coming of a messenger who prepares the way for the Lord, linking to New Testament themes.
• Other prophets like Zephaniah, Micah, and Obadiah focus on different themes, such as judgment and social justice, rather than the specific messianic hope found in Malachi.

This understanding of Malachi's role in the prophetic tradition is crucial for grasping the continuity between the Old and New Testaments, particularly regarding the expectation of the Messiah.