How does the book of Ruth uniquely contribute to the broader narrative of the Old Testament regarding God's covenant and inclusion?

A It demonstrates the importance of strict adherence to Jewish law to maintain purity of lineage. B It highlights God's faithfulness to the Davidic line, regardless of the moral failings of individuals. C It challenges the idea of ethnic exclusivity by showcasing a Moabite woman becoming part of the lineage of King David and ultimately Jesus. D It serves as a warning against intermarriage with foreign women due to the risk of idolatry.