Which city did David capture from the Jebusites and call the City of David?

Answer: Jerusalem

David captured the fortress of Zion in Jerusalem, though the Jebusites boasted that he could never get in.

“Now the king and his men marched to Jerusalem against the Jebusites who inhabited the land. The Jebusites said to David: “You will never get in here. Even the blind and lame can repel you.” For they thought, “David cannot get in here.””— 2 Samuel 5:6 (BSB)