In the book of Ruth, beyond the love story, what legal and cultural practice ensured the continuation of Naomi's family line and the inheritance of Elimelech's land?

A The practice of levirate marriage, where a close relative of the deceased husband was obligated to marry the widow to provide an heir. B The practice of offering a sacrifice to the local deities to ensure fertility and prosperity. C The practice of selling the land to a foreign buyer to generate income for Naomi. D The practice of adopting a child from another tribe to continue the family name.