My oppinon I think its C.I might be wrong but that might make the most since.
A written legal code would be am improvement over an oral set of laws because citizens may forget laws, depending on how much there are. Having them written, where everyone can read it, may help them better understand and remember the acts/laws.
The answer is A: 6th century BC. The Vedas are extremely old Indian, Hindu based scriptures. In fact, other scriptures including the Veda's may predate the dates given to them by modern historians.