During the Reign of Zhu Di,the Appearance and Quality of Chinese

Multiple Choice

During the reign of Zhu Di,the appearance and quality of Chinese porcelain improved dramatically.Why?

A) The court official Zheng He expanded the style and subject of images used in the porcelain.
B) The "treasure fleet" of Chinese trade vessels acquired cobalt ore, creating a rich color in the porcelain.
C) Zheng He perfected a new firing process for porcelain.
D) Raw materials and minerals used in the new porcelain were imported from Europe.