In the book of Acts, what was the key theological significance of Peter's visit to Cornelius' house (Acts 10), a Gentile, beyond simply converting an individual?

A It primarily signified the end of Jewish dietary laws for Jewish Christians. B It primarily demonstrated Peter's superior authority over the other apostles. C It primarily highlighted the importance of baptism by immersion for salvation. D It signified God's acceptance of Gentiles into the Christian community, breaking down the barrier between Jews and Gentiles and expanding the Gospel's reach.