What was the likely purpose of the 'Urim and Thummim' used by the High Priest, and how were they likely used to discern God's will?

A They were precious stones used for divination, with different colors representing 'yes' or 'no' answers. B They were dice-like objects cast to determine God's will through a complex system of numerology. C They were lots cast to obtain a binary (yes/no) answer from God, likely kept in the breastplate of judgment. D They were small scrolls containing cryptic prophecies, deciphered through a process of dream interpretation.