Final answer:
Luke 2:4 indicates that King David was one of Joseph's ancestors.
Step-by-step explanation:
According to Luke 2:4, one of Joseph's ancestors was King David. Joseph also belonged to the House of David, which is a significant detail in the gospel narratives, as it connects Jesus with Davidic lineage, fulfilling the prophecy that the Messiah would come from David's line. Although the passage in Luke does not directly mention the name 'King David,' it states that Joseph went to Bethlehem, 'the city of David,' because he was of the house and lineage of David. Therefore, the intended answer is King David.