How does the book of Ruth uniquely contribute to the overall narrative of the Old Testament?

A It provides a historical account of the construction of the Second Temple in Jerusalem. B It illustrates God's providential care and inclusion of Gentiles into the lineage of Jesus Christ, challenging notions of ethnic exclusivity. C It outlines the specific laws and regulations governing the priestly duties in the Tabernacle. D It recounts the military campaigns of King David and the expansion of the Israelite kingdom.