Which of his many wives did King Rehoboam love most?

Answer: Maacah daughter of Absalom

Rehoboam had 18 wives and 60 concubines but loved Maacah, Absalom's daughter, most, and made her son Abijah chief prince.

“Rehoboam loved Maacah daughter of Absalom more than all his wives and concubines. In all, he had eighteen wives and sixty concubines, and he was the father of twenty-eight sons and sixty daughters. Rehoboam appointed Abijah son of Maacah as chief prince among his brothers, intending to make him king.”— 2 Chronicles 11:21-22 (BSB)