Because there had been many improvements made to succeed. Weaponry, generals, and tactics had changed. There was also more of a drive. The angrier the person,the more determined they are.
Harper's Ferry was a ship with a large arsenal.
I would say c, but don't quote me on that.
Besides silk, the Chinese also exported (sold) teas, salt, sugar, porcelain, and spices. Most of what was traded was expensive luxury goods. This was because it was a long trip and merchants didn't have a lot of room for goods. They imported, or bought, goods like cotton, ivory, wool, gold, and silver.