The division of the Roman Empire into eastern and western halves was a crucial step in the formation of the "Byzantine Empire", since this Empire "grew" in many ways from the former.
It protected the sultan's power by providing him with a group of extremely loyal officials and soldiers is why the Devshirme system was so important to the Ottoman Empire. The correct option among all the options that are given in the question is the fourth option or option "D". I hope the answer comes to your help.