D. Castiglione
Cesare Borgia was the Son of the Pope and Cosimo de Medici's family ruled Florence, so neither have anything to do with the royal family of Mantua. Machiavelli wrote the Prince, so that is not the correct answer either. Castiglione was part of the Royal family of Mantua and did write the Book of the Courtier. So D is the correct answer.
Answer:
Explanation:
At its most basic, Christianity is the faith tradition that focuses on the figure of Jesus Christ. In this context, faith refers both to the believers' act of trust and to the content of their faith. As a tradition, Christianity is more than a system of religious belief.