Final answer:
The right to due process originally comes from the Magna Carta (a), an English document from 1215 that set the stage for later legal principles, such as those in the U.S. Constitution.
Step-by-step explanation:
The idea of an accused person's right to due process was originally found in the Magna Carta, signed in 1215, which is correctly identified as option (a) Magna Carta. The Magna Carta is a foundational document in English constitutional law and laid the groundwork for the concept of due process.
It specifically included protections such as a free man not being penalized unless there was a lawful judgment by his peers, which anticipated later legal principles encompassed within the Fifth and Sixth Amendments to the U.S. Constitution established several centuries later.
While initially protecting the rights of English barons, the scope of Magna Carta expanded over time, with English subjects, including those in North America, regarding it as a bedrock of liberties for all free men. The historical significance of Magna Carta extended beyond its immediate impact in medieval England to influencing constitutional developments in various countries, demonstrating the wide reach of its principles.