The original story of Mahabharata was probably composed by:

Charioteer-bards known as Sutas

The correct answer is Option (1) → Charioteer-bards known as Sutas

The original story was probably composed by charioteer-bards known as sutas who generally accompanied Kshatriya warriors to the battlefield and composed poems celebrating their victories and other achievements. These compositions circulated orally. Then, from the fifth century BCE, Brahmanas took over the story and began to commit it to writing. This was the time when chiefdoms such as those of the Kurus and  Panchalas, around whom the story of the epic revolves, were gradually becoming kingdoms.