In the book of Ruth, what is the significance of Boaz's act of 'redeeming' Ruth and Naomi's land, going beyond simply buying property?

A It was a clever business transaction to increase his own wealth. B It fulfilled the legal requirement to prevent the land from being sold outside the tribe, and to provide an heir for the deceased. C It was a way to publicly humiliate Naomi and Ruth. D It was primarily motivated by his attraction to Ruth's foreign beauty.