In the following descriptions related to Tang Dynasty, which one is NOT correct?
A.
The prosperity of the early Tang Dynasty was attributed to Emperor Taizong, this period in history was also known as the "Reign of Kaiyuan".
B.
Capital city Chang’an became the first international metropolis with a population of over 1,000,000 people.
C.
Wu Zetian is the only female emperor in Chinese history.
D.
Concubine Yang and emperor’s wrong appointment of her relatives should be partly blamed for the decline of Tang Dynasty.