What was the significance of the 'ephod' in the Old Testament, particularly regarding its use by priests and its association with seeking divine guidance?

A It was a type of incense used in temple rituals. B It was a musical instrument used during worship services. C It was a linen garment worn by priests, sometimes used in conjunction with the Urim and Thummim to discern God's will. D It was a specific type of offering made during the Day of Atonement.