From whom did Abraham buy the field and cave to bury Sarah?

Answer: Ephron the Hittite

Abraham weighed out four hundred shekels of silver to Ephron the Hittite for the field and its cave.

“Now Ephron was sitting among the sons of Heth. So in the presence of all the Hittites who had come to the gate of his city, Ephron the Hittite answered Abraham,”— Genesis 23:10 (BSB)