Do you have a real question or answers?
This isn't hard to answer - A; because Japan had so many small, isolated islands, governing the entire country was often very challengin. Imagine being the emperor or just in charge of a country which was composed of hundreds of islands. For your decree to get into motion on all of them, it needed a lot of time.
2. Lords
1. Knights
4. Church
3. Serfs
They did a trading chain and traded items
