The tables were written down to settle a social conflict between the patricians (the ruling class) and the plebeians. Both were trying to have advantage in this conflict using different means, and it was felt that a proper procedure in such conflich, which would ensure a stabilisation in the country, as no more such chaotic conflicts would take place.
A primary source is a source that was created by a person who was there to witness it. So, the answer would be A, a document made by someone who actually saw an event. In other words, the document was written by someone who was there to witness the event.
