Which king of Babylon conquered Jerusalem?

Answer: Nebuchadnezzar

The servants of Nebuchadnezzar king of Babylon besieged Jerusalem, and Nebuchadnezzar himself came to the city during the siege.

“At that time the servants of Nebuchadnezzar king of Babylon marched up to Jerusalem, and the city came under siege. And Nebuchadnezzar king of Babylon came to the city while his servants were besieging it.”— 2 Kings 24:10-11 (BSB)