Final answer:
The four books of the Justinian code, known as Digesta, Institutiones, Codex, and Novellae, were a legal compilation meant to streamline and preserve Roman laws under Emperor Justinian.
Step-by-step explanation:
The name of the four books of the Justinian code is A. Digesta, Institutiones, Codex, Novellae. The main purpose of these books was to serve as a legal compilation of Roman laws. This collection, known as the Corpus Juris Civilis, was a monumental legal project carried out by Emperor Justinian to compile and edit Roman edicts issued from the early second to the sixth century CE. The Code of Justinian regulated imperial edicts by addressing inconsistencies among them. It also incorporated the written opinions of jurists, and through this compilation, Justinian not only preserved the legal history but also imposed Roman law on his subjects, seeing it as an aspect of Roman unity.