Who did Solomon attempt to kill, who later became king of Israel?

The correct answer is Jeroboam. Solomon attempted to kill Jeroboam because he perceived him as a threat to his reign. Jeroboam was a high-ranking official in Solomon's court and was prophesied to become a ruler over ten tribes of Israel, which posed a direct challenge to Solomon's authority. This prophecy was delivered by the prophet Ahijah, which indicated that Jeroboam would lead a significant portion of the kingdom after Solomon’s death.

Jeroboam fled to Egypt for safety and returned after Solomon's death, eventually becoming the first king of the northern kingdom of Israel. His leadership marked a crucial division in Israel’s monarchy, as he established a separate entity from the southern kingdom of Judah, led by Solomon's son, Rehoboam.

In contrast, Adonijah is notable for attempting to claim the throne after David's death but was not specifically targeted for assassination by Solomon. Rehoboam was Solomon's son and, thus, not a candidate Solomon would seek to eliminate. Absalom was a son of David who rebelled against his father but had already died prior to Solomon's reign.